[SPARK-20278][R] Disable 'multiple_dots_linter' lint rule that is against project's code style
[SPARK-20278][R] Disable 'multiple_dots_linter' lint rule that is against project's code style

## What changes were proposed in this pull request?

Currently, multi-dot separated variables in R is not allowed. For example,

```diff
 setMethod("from_json", signature(x = "Column", schema = "structType"),
-          function(x, schema, asJsonArray = FALSE, ...) {
+          function(x, schema, as.json.array = FALSE, ...) {
             if (asJsonArray) {
               jschema <- callJStatic("org.apache.spark.sql.types.DataTypes",
                                      "createArrayType",
```

produces an error as below:

```
R/functions.R:2462:31: style: Words within variable and function names should be separated by '_' rather than '.'.
          function(x, schema, as.json.array = FALSE, ...) {
                              ^~~~~~~~~~~~~
```

This seems against https://google.github.io/styleguide/Rguide.xml#identifiers which says

> The preferred form for variable names is all lower case letters and words separated with dots

This looks because lintr by default https://github.com/jimhester/lintr follows http://r-pkgs.had.co.nz/style.html as written in the README.md. Few cases seems not following Google's one as "a few tweaks".

Per [SPARK-6813](https://issues.apache.org/jira/browse/SPARK-6813), we follow Google's R Style Guide with few exceptions https://google.github.io/styleguide/Rguide.xml. This is also merged into Spark's website - https://github.com/apache/spark-website/pull/43

Also, it looks we have no limit on function name. This rule also looks affecting to the name of functions as written in the README.md.

> `multiple_dots_linter`: check that function and variable names are separated by _ rather than ..

## How was this patch tested?

Manually tested `./dev/lint-r`with the manual change below in `R/functions.R`:

```diff
 setMethod("from_json", signature(x = "Column", schema = "structType"),
-          function(x, schema, asJsonArray = FALSE, ...) {
+          function(x, schema, as.json.array = FALSE, ...) {
             if (asJsonArray) {
               jschema <- callJStatic("org.apache.spark.sql.types.DataTypes",
                                      "createArrayType",
```

**Before**

```R
R/functions.R:2462:31: style: Words within variable and function names should be separated by '_' rather than '.'.
          function(x, schema, as.json.array = FALSE, ...) {
                              ^~~~~~~~~~~~~
```

**After**

```
lintr checks passed.
```

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #17590 from HyukjinKwon/disable-dot-in-name.

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