[SPARK-19106][DOCS] Styling for the configuration docs is broken
[SPARK-19106][DOCS] Styling for the configuration docs is broken

## What changes were proposed in this pull request?

configuration.html section headings were not specified correctly in markdown and weren't rendering, being recognized correctly. Removed extra p tags and pulled level 4 titles up to level 3, since level 3 had been skipped. This improves the TOC.

## How was this patch tested?

Doc build, manual check.

Author: Sean Owen <sowen@cloudera.com>

Closes #16490 from srowen/SPARK-19106.

rednaxelafx/apache-spark,loneknightpy/spark,xflin/spark,mike0sv/spark,aokolnychyi/spark,bravo-zhang/spark,kissmetrics/spark,nchammas/spark,techaddict/spark,hvanhovell/spark,mdespriee/spark,WindCanDie/spark,bdrillard/spark,jlopezmalla/spark,zero323/spark,chuckchen/spark,shaneknapp/spark,dongjoon-hyun/spark,jkbradley/spark,guoxiaolongzte/spark,sachintyagi22/spark,shaneknapp/spark,mahak/spark,UndeadBaneGitHub/spark,aosagie/spark,vinodkc/spark,brad-kaiser/spark,joseph-torres/spark,apache/spark,ueshin/apache-spark,witgo/spark,liyichao/spark,maropu/spark,ahnqirage/spark,hvanhovell/spark,ptkool/spark,jianran/spark,ioana-delaney/spark,markhamstra/spark,saturday-shi/spark,andrewor14/spark,huang1900/spark,zhouyejoe/spark,someorz/spark,dongjoon-hyun/spark,Aegeaner/spark,ptkool/spark,markhamstra/spark,map222/spark,yanboliang/spark,darionyaphet/spark,pgandhi999/spark,SHASHANKB/spark,nilsgrabbert/spark,highfei2011/spark,hhbyyh/spark,saltstar/spark,cloud-fan/spark,rikima/spark,sachintyagi22/spark,map222/spark,taroplus/spark,JerryLead/spark,LantaoJin/spark,HyukjinKwon/spark,kevinyu98/spark,ahnqirage/spark,yanboliang/spark,byakuinss/spark,rekhajoshm/spark,ericvandenbergfb/spark,shaneknapp/spark,gengliangwang/spark,goldmedal/spark,chuckchen/spark,rikima/spark,ptkool/spark,bdrillard/spark,xflin/spark,Aegeaner/spark,andrewor14/spark,ericvandenbergfb/spark,pgandhi999/spark,holdenk/spark,akopich/spark,jrshust/spark,mahak/spark,LantaoJin/spark,dongjoon-hyun/spark,1haodian/spark,xflin/spark,shaneknapp/spark,adrian-ionescu/apache-spark,mzl9039/spark,dhruve/spark,sahilTakiar/spark,mzl9039/spark,Aegeaner/spark,wangyum/spark,poffuomo/spark,debugger87/spark,esi-mineset/spark,maropu/spark,brad-kaiser/spark,WeichenXu123/spark,srowen/spark,WindCanDie/spark,setjet/spark,liyichao/spark,debugger87/spark,chuckchen/spark,icexelloss/spark,rekhajoshm/spark,LantaoJin/spark,szhem/spark,milliman/spark,cin/spark,ueshin/apache-spark,shuangshuangwang/spark,jlopezmalla/spark,witgo/spark,aokolnychyi/spark,gengliangwang/spark,loneknightpy/spark,wangmiao1981/spark,esi-mineset/spark,eyalfa/spark,goldmedal/spark,ericvandenbergfb/spark,wangmiao1981/spark,ddna1021/spark,nilsgrabbert/spark,wzhfy/spark,JoshRosen/spark,zhouyejoe/spark,loneknightpy/spark,JoshRosen/spark,alunarbeach/spark,szhem/spark,minixalpha/spark,actuaryzhang/spark,ron8hu/spark,xuanyuanking/spark,huang1900/spark,pgandhi999/spark,rednaxelafx/apache-spark,jkbradley/spark,shaneknapp/spark,zhouyejoe/spark,aokolnychyi/spark,icexelloss/spark,apache-spark-on-k8s/spark,ueshin/apache-spark,icexelloss/spark,liutang123/spark,panfengfeng/spark,wzhfy/spark,bdrillard/spark,milliman/spark,zzcclp/spark,debugger87/spark,xflin/spark,nlalevee/spark,apache/spark,dbtsai/spark,andrewor14/spark,ptkool/spark,ConeyLiu/spark,ericvandenbergfb/spark,techaddict/spark,eyalfa/spark,xuanyuanking/spark,cin/spark,gengliangwang/spark,liutang123/spark,guoxiaolongzte/spark,hvanhovell/spark,mike0sv/spark,darionyaphet/spark,ioana-delaney/spark,facaiy/spark,matthewfranglen/spark,jlopezmalla/spark,icexelloss/spark,shuangshuangwang/spark,debugger87/spark,UndeadBaneGitHub/spark,wangyum/spark,loneknightpy/spark,tejasapatil/spark,SHASHANKB/spark,liyichao/spark,poffuomo/spark,bOOm-X/spark,brad-kaiser/spark,srowen/spark,setjet/spark,HyukjinKwon/spark,rekhajoshm/spark,sachintyagi22/spark,panfengfeng/spark,apache/spark,joseph-torres/spark,esi-mineset/spark,aray/spark,jiangxb1987/spark,markhamstra/spark,actuaryzhang/spark,kiszk/spark,esi-mineset/spark,ahnqirage/spark,zero323/spark,debugger87/spark,bravo-zhang/spark,UndeadBaneGitHub/spark,publicRoman/spark,rikima/spark,chuckchen/spark,JoshRosen/spark,bravo-zhang/spark,jiangxb1987/spark,BryanCutler/spark,JerryLead/spark,bOOm-X/spark,witgo/spark,zuotingbing/spark,skonto/spark,szhem/spark,kissmetrics/spark,ConeyLiu/spark,pgandhi999/spark,setjet/spark,WindCanDie/spark,michalsenkyr/spark,byakuinss/spark,apache-spark-on-k8s/spark,dbtsai/spark,dhruve/spark,narahari92/spark,cloud-fan/spark,facaiy/spark,hhbyyh/spark,jrshust/spark,joseph-torres/spark,HyukjinKwon/spark,actuaryzhang/spark,taroplus/spark,nchammas/spark,adrian-ionescu/apache-spark,sureshthalamati/spark,rednaxelafx/apache-spark,loneknightpy/spark,mdespriee/spark,ajaysaini725/spark,saltstar/spark,apache/spark,jlopezmalla/spark,jianran/spark,milliman/spark,holdenk/spark,huang1900/spark,shuangshuangwang/spark,narahari92/spark,1haodian/spark,setjet/spark,cloud-fan/spark,mdespriee/spark,1haodian/spark,apache/spark,andrewor14/spark,dongjoon-hyun/spark,tejasapatil/spark,eyalfa/spark,patrick-nicholson/spark,apache-spark-on-k8s/spark,nlalevee/spark,facaiy/spark,poffuomo/spark,rezasafi/spark,jkbradley/spark,wangyum/spark,hhbyyh/spark,narahari92/spark,WeichenXu123/spark,lxsmnv/spark,holdenk/spark,maropu/spark,taroplus/spark,srowen/spark,kevinyu98/spark,chuckchen/spark,goldmedal/spark,cloud-fan/spark,liyichao/spark,ioana-delaney/spark,debugger87/spark,ericvandenbergfb/spark,liyichao/spark,kevinyu98/spark,bdrillard/spark,MLnick/spark,panfengfeng/spark,JerryLead/spark,minixalpha/spark,bOOm-X/spark,adrian-ionescu/apache-spark,actuaryzhang/spark,milliman/spark,bdrillard/spark,JoshRosen/spark,ddna1021/spark,kiszk/spark,gengliangwang/spark,patrick-nicholson/spark,rednaxelafx/apache-spark,alunarbeach/spark,dhruve/spark,aray/spark,narahari92/spark,lvdongr/spark,ahnqirage/spark,minixalpha/spark,witgo/spark,hvanhovell/spark,sureshthalamati/spark,shuangshuangwang/spark,srowen/spark,holdenk/spark,andrewor14/spark,dhruve/spark,rekhajoshm/spark,rekhajoshm/spark,JoshRosen/spark,nlalevee/spark,shuangshuangwang/spark,HyukjinKwon/spark,skonto/spark,bravo-zhang/spark,narahari92/spark,michalsenkyr/spark,witgo/spark,jrshust/spark,spark-test/spark,someorz/spark,jiangxb1987/spark,aosagie/spark,narahari92/spark,yanboliang/spark,sahilTakiar/spark,akopich/spark,joseph-torres/spark,WeichenXu123/spark,ron8hu/spark,tejasapatil/spark,cloud-fan/spark,BryanCutler/spark,sahilTakiar/spark,zuotingbing/spark,lxsmnv/spark,bOOm-X/spark,techaddict/spark,MLnick/spark,sahilTakiar/spark,maropu/spark,someorz/spark,rezasafi/spark,shubhamchopra/spark,hhbyyh/spark,adrian-ionescu/apache-spark,spark-test/spark,minixalpha/spark,apache-spark-on-k8s/spark,maropu/spark,cin/spark,MLnick/spark,wangmiao1981/spark,jiangxb1987/spark,akopich/spark,JerryLead/spark,xflin/spark,stanzhai/spark,someorz/spark,maropu/spark,zero323/spark,ConeyLiu/spark,huang1900/spark,mahak/spark,rikima/spark,shubhamchopra/spark,poffuomo/spark,ueshin/apache-spark,tengpeng/spark,alunarbeach/spark,kissmetrics/spark,ron8hu/spark,1haodian/spark,tengpeng/spark,ddna1021/spark,dongjoon-hyun/spark,wangyum/spark,JoshRosen/spark,bdrillard/spark,esi-mineset/spark,eyalfa/spark,darionyaphet/spark,darionyaphet/spark,ajaysaini725/spark,lxsmnv/spark,hhbyyh/spark,zzcclp/spark,stanzhai/spark,janewangfb/spark,jkbradley/spark,janewangfb/spark,zhouyejoe/spark,ConeyLiu/spark,highfei2011/spark,lxsmnv/spark,nchammas/spark,markhamstra/spark,MLnick/spark,dongjoon-hyun/spark,UndeadBaneGitHub/spark,poffuomo/spark,liutang123/spark,esi-mineset/spark,goldmedal/spark,hvanhovell/spark,milliman/spark,dongjoon-hyun/spark,SHASHANKB/spark,BryanCutler/spark,janewangfb/spark,setjet/spark,skonto/spark,WindCanDie/spark,ueshin/apache-spark,highfei2011/spark,debugger87/spark,zhouyejoe/spark,nlalevee/spark,kiszk/spark,apache/spark,mdespriee/spark,nilsgrabbert/spark,mike0sv/spark,aray/spark,ajaysaini725/spark,liutang123/spark,taroplus/spark,michalsenkyr/spark,lvdongr/spark,jrshust/spark,shaneknapp/spark,tejasapatil/spark,cin/spark,facaiy/spark,saltstar/spark,mzl9039/spark,tejasapatil/spark,michalsenkyr/spark,nchammas/spark,eyalfa/spark,aosagie/spark,guoxiaolongzte/spark,aray/spark,mdespriee/spark,kiszk/spark,yanboliang/spark,cin/spark,jiangxb1987/spark,rezasafi/spark,ajaysaini725/spark,tejasapatil/spark,JerryLead/spark,gengliangwang/spark,andrewor14/spark,byakuinss/spark,zuotingbing/spark,taroplus/spark,xuanyuanking/spark,lvdongr/spark,holdenk/spark,tengpeng/spark,setjet/spark,highfei2011/spark,zero323/spark,rezasafi/spark,michalsenkyr/spark,darionyaphet/spark,janewangfb/spark,aray/spark,byakuinss/spark,ericvandenbergfb/spark,holdenk/spark,ueshin/apache-spark,ioana-delaney/spark,actuaryzhang/spark,mzl9039/spark,ron8hu/spark,rezasafi/spark,highfei2011/spark,ConeyLiu/spark,rednaxelafx/apache-spark,sahilTakiar/spark,wzhfy/spark,gengliangwang/spark,saturday-shi/spark,wzhfy/spark,1haodian/spark,dbtsai/spark,bravo-zhang/spark,joseph-torres/spark,akopich/spark,facaiy/spark,dhruve/spark,zzcclp/spark,janewangfb/spark,wzhfy/spark,shubhamchopra/spark,stanzhai/spark,alunarbeach/spark,mahak/spark,stanzhai/spark,apache-spark-on-k8s/spark,LantaoJin/spark,aokolnychyi/spark,kiszk/spark,ericvandenbergfb/spark,dhruve/spark,michalsenkyr/spark,ddna1021/spark,publicRoman/spark,zuotingbing/spark,sahilTakiar/spark,vinodkc/spark,WindCanDie/spark,mdespriee/spark,ron8hu/spark,lvdongr/spark,yanboliang/spark,rekhajoshm/spark,byakuinss/spark,liyichao/spark,ahnqirage/spark,map222/spark,saturday-shi/spark,brad-kaiser/spark,stanzhai/spark,chuckchen/spark,alunarbeach/spark,akopich/spark,Aegeaner/spark,techaddict/spark,publicRoman/spark,loneknightpy/spark,brad-kaiser/spark,MLnick/spark,jlopezmalla/spark,xuanyuanking/spark,szhem/spark,aokolnychyi/spark,apache-spark-on-k8s/spark,rezasafi/spark,jianran/spark,loneknightpy/spark,markhamstra/spark,ConeyLiu/spark,map222/spark,UndeadBaneGitHub/spark,yanboliang/spark,MLnick/spark,zuotingbing/spark,wangmiao1981/spark,aosagie/spark,bOOm-X/spark,someorz/spark,panfengfeng/spark,mike0sv/spark,jkbradley/spark,SHASHANKB/spark,ptkool/spark,poffuomo/spark,BryanCutler/spark,mike0sv/spark,Aegeaner/spark,gengliangwang/spark,BryanCutler/spark,michalsenkyr/spark,xuanyuanking/spark,jkbradley/spark,jrshust/spark,joseph-torres/spark,map222/spark,WindCanDie/spark,aray/spark,highfei2011/spark,sachintyagi22/spark,darionyaphet/spark,patrick-nicholson/spark,Aegeaner/spark,goldmedal/spark,alunarbeach/spark,mahak/spark,witgo/spark,sachintyagi22/spark,guoxiaolongzte/spark,aosagie/spark,saturday-shi/spark,andrewor14/spark,highfei2011/spark,rekhajoshm/spark,ajaysaini725/spark,byakuinss/spark,adrian-ionescu/apache-spark,nlalevee/spark,caneGuy/spark,tengpeng/spark,poffuomo/spark,nchammas/spark,aray/spark,janewangfb/spark,LantaoJin/spark,minixalpha/spark,kissmetrics/spark,lxsmnv/spark,tejasapatil/spark,ahnqirage/spark,spark-test/spark,tengpeng/spark,WindCanDie/spark,markhamstra/spark,shubhamchopra/spark,bOOm-X/spark,bOOm-X/spark,rezasafi/spark,shubhamchopra/spark,rednaxelafx/apache-spark,srowen/spark,hvanhovell/spark,panfengfeng/spark,ddna1021/spark,spark-test/spark,ddna1021/spark,sureshthalamati/spark,caneGuy/spark,rednaxelafx/apache-spark,szhem/spark,ioana-delaney/spark,sureshthalamati/spark,techaddict/spark,lvdongr/spark,HyukjinKwon/spark,sureshthalamati/spark,pgandhi999/spark,1haodian/spark,mdespriee/spark,markhamstra/spark,icexelloss/spark,actuaryzhang/spark,mahak/spark,bravo-zhang/spark,xflin/spark,taroplus/spark,wzhfy/spark,caneGuy/spark,esi-mineset/spark,dbtsai/spark,ueshin/apache-spark,tengpeng/spark,goldmedal/spark,alunarbeach/spark,kissmetrics/spark,nlalevee/spark,map222/spark,cin/spark,nilsgrabbert/spark,saltstar/spark,xflin/spark,bdrillard/spark,stanzhai/spark,liutang123/spark,publicRoman/spark,nchammas/spark,ioana-delaney/spark,icexelloss/spark,vinodkc/spark,nlalevee/spark,witgo/spark,jianran/spark,jlopezmalla/spark,akopich/spark,jrshust/spark,rikima/spark,zzcclp/spark,LantaoJin/spark,liyichao/spark,dbtsai/spark,patrick-nicholson/spark,mike0sv/spark,vinodkc/spark,jianran/spark,wangyum/spark,vinodkc/spark,liutang123/spark,sureshthalamati/spark,1haodian/spark,facaiy/spark,xuanyuanking/spark,kiszk/spark,zhouyejoe/spark,patrick-nicholson/spark,kevinyu98/spark,vinodkc/spark,mahak/spark,SHASHANKB/spark,shubhamchopra/spark,milliman/spark,saturday-shi/spark,skonto/spark,huang1900/spark,ajaysaini725/spark,jiangxb1987/spark,saturday-shi/spark,SHASHANKB/spark,sureshthalamati/spark,JerryLead/spark,kevinyu98/spark,facaiy/spark,someorz/spark,JerryLead/spark,lxsmnv/spark,vinodkc/spark,spark-test/spark,huang1900/spark,WeichenXu123/spark,milliman/spark,joseph-torres/spark,mzl9039/spark,HyukjinKwon/spark,skonto/spark,skonto/spark,WeichenXu123/spark,szhem/spark,chuckchen/spark,spark-test/spark,shuangshuangwang/spark,caneGuy/spark,minixalpha/spark,nilsgrabbert/spark,spark-test/spark,taroplus/spark,adrian-ionescu/apache-spark,UndeadBaneGitHub/spark,huang1900/spark,caneGuy/spark,caneGuy/spark,skonto/spark,cloud-fan/spark,zero323/spark,techaddict/spark,zzcclp/spark,LantaoJin/spark,JoshRosen/spark,pgandhi999/spark,someorz/spark,zzcclp/spark,publicRoman/spark,wzhfy/spark,ioana-delaney/spark,brad-kaiser/spark,lxsmnv/spark,ahnqirage/spark,goldmedal/spark,eyalfa/spark,guoxiaolongzte/spark,jlopezmalla/spark,guoxiaolongzte/spark,publicRoman/spark,dbtsai/spark,wangyum/spark,kiszk/spark,icexelloss/spark,ConeyLiu/spark,wangmiao1981/spark,publicRoman/spark,szhem/spark,apache-spark-on-k8s/spark,cloud-fan/spark,kissmetrics/spark,kevinyu98/spark,lvdongr/spark,ptkool/spark,patrick-nicholson/spark,hhbyyh/spark,saltstar/spark,adrian-ionescu/apache-spark,panfengfeng/spark,aosagie/spark,eyalfa/spark,janewangfb/spark,rikima/spark,narahari92/spark,guoxiaolongzte/spark,saltstar/spark,dhruve/spark,Aegeaner/spark,darionyaphet/spark,UndeadBaneGitHub/spark,caneGuy/spark,WeichenXu123/spark,setjet/spark,srowen/spark,BryanCutler/spark,mzl9039/spark,nilsgrabbert/spark,BryanCutler/spark,panfengfeng/spark,nilsgrabbert/spark,patrick-nicholson/spark,SHASHANKB/spark,mzl9039/spark,actuaryzhang/spark,pgandhi999/spark,aosagie/spark,zzcclp/spark,jiangxb1987/spark,sachintyagi22/spark,jkbradley/spark,brad-kaiser/spark,xuanyuanking/spark,saturday-shi/spark,cin/spark,ptkool/spark,kevinyu98/spark,zuotingbing/spark,yanboliang/spark,shaneknapp/spark,saltstar/spark,techaddict/spark,MLnick/spark,maropu/spark,liutang123/spark,ron8hu/spark,sahilTakiar/spark,byakuinss/spark,zero323/spark,aokolnychyi/spark,minixalpha/spark,kissmetrics/spark,jrshust/spark,holdenk/spark,ddna1021/spark,aokolnychyi/spark,map222/spark,dbtsai/spark,HyukjinKwon/spark,mike0sv/spark,srowen/spark,wangyum/spark,jianran/spark,wangmiao1981/spark,ajaysaini725/spark,shubhamchopra/spark,stanzhai/spark,zhouyejoe/spark,WeichenXu123/spark,rikima/spark,tengpeng/spark,zero323/spark,jianran/spark,wangmiao1981/spark,zuotingbing/spark,hvanhovell/spark,hhbyyh/spark,akopich/spark,ron8hu/spark,nchammas/spark,apache/spark,shuangshuangwang/spark,sachintyagi22/spark,lvdongr/spark,bravo-zhang/spark