docs/modules/categories.rst: Add a reference to DiagramGrid.
docs/modules/categories.rst: Add a reference to DiagramGrid.

toolforger/sympy,farhaanbukhsh/sympy,garvitr/sympy,hrashk/sympy,lidavidm/sympy,kmacinnis/sympy,ga7g08/sympy,iamutkarshtiwari/sympy,Sumith1896/sympy,Shaswat27/sympy,skirpichev/omg,hargup/sympy,emon10005/sympy,jamesblunt/sympy,mafiya69/sympy,meghana1995/sympy,Arafatk/sympy,grevutiu-gabriel/sympy,madan96/sympy,cswiercz/sympy,AunShiLord/sympy,kaichogami/sympy,debugger22/sympy,Gadal/sympy,shikil/sympy,abloomston/sympy,toolforger/sympy,yashsharan/sympy,wanglongqi/sympy,srjoglekar246/sympy,jerli/sympy,sunny94/temp,Sumith1896/sympy,drufat/sympy,AkademieOlympia/sympy,debugger22/sympy,liangjiaxing/sympy,abhiii5459/sympy,moble/sympy,ahhda/sympy,Vishluck/sympy,Gadal/sympy,yukoba/sympy,hargup/sympy,MridulS/sympy,wyom/sympy,moble/sympy,yukoba/sympy,Designist/sympy,abloomston/sympy,MechCoder/sympy,bukzor/sympy,jamesblunt/sympy,kevalds51/sympy,aktech/sympy,rahuldan/sympy,grevutiu-gabriel/sympy,kaichogami/sympy,Mitchkoens/sympy,madan96/sympy,atreyv/sympy,souravsingh/sympy,Shaswat27/sympy,pandeyadarsh/sympy,Davidjohnwilson/sympy,jaimahajan1997/sympy,AkademieOlympia/sympy,garvitr/sympy,VaibhavAgarwalVA/sympy,sampadsaha5/sympy,Designist/sympy,sampadsaha5/sympy,saurabhjn76/sympy,skidzo/sympy,yashsharan/sympy,MechCoder/sympy,Curious72/sympy,kmacinnis/sympy,kmacinnis/sympy,jbbskinny/sympy,ga7g08/sympy,grevutiu-gabriel/sympy,moble/sympy,Curious72/sympy,mafiya69/sympy,postvakje/sympy,ChristinaZografou/sympy,jerli/sympy,kevalds51/sympy,jamesblunt/sympy,toolforger/sympy,ChristinaZografou/sympy,drufat/sympy,kaichogami/sympy,sahmed95/sympy,saurabhjn76/sympy,cccfran/sympy,atreyv/sympy,beni55/sympy,asm666/sympy,shikil/sympy,Shaswat27/sympy,pandeyadarsh/sympy,mafiya69/sympy,wyom/sympy,Titan-C/sympy,MechCoder/sympy,AkademieOlympia/sympy,oliverlee/sympy,cswiercz/sympy,amitjamadagni/sympy,Titan-C/sympy,Vishluck/sympy,jaimahajan1997/sympy,hrashk/sympy,kaushik94/sympy,cswiercz/sympy,Gadal/sympy,drufat/sympy,shipci/sympy,vipulroxx/sympy,ahhda/sympy,jaimahajan1997/sympy,ahhda/sympy,beni55/sympy,atsao72/sympy,shipci/sympy,MridulS/sympy,kumarkrishna/sympy,sahilshekhawat/sympy,lindsayad/sympy,maniteja123/sympy,saurabhjn76/sympy,kumarkrishna/sympy,Designist/sympy,liangjiaxing/sympy,meghana1995/sympy,Curious72/sympy,Vishluck/sympy,vipulroxx/sympy,diofant/diofant,abloomston/sympy,kaushik94/sympy,wyom/sympy,jerli/sympy,wanglongqi/sympy,rahuldan/sympy,souravsingh/sympy,VaibhavAgarwalVA/sympy,yukoba/sympy,emon10005/sympy,meghana1995/sympy,sahmed95/sympy,dqnykamp/sympy,mcdaniel67/sympy,postvakje/sympy,sahilshekhawat/sympy,pbrady/sympy,Davidjohnwilson/sympy,chaffra/sympy,asm666/sympy,rahuldan/sympy,oliverlee/sympy,abhiii5459/sympy,yashsharan/sympy,cccfran/sympy,liangjiaxing/sympy,souravsingh/sympy,aktech/sympy,asm666/sympy,bukzor/sympy,Sumith1896/sympy,kaushik94/sympy,ga7g08/sympy,amitjamadagni/sympy,shipci/sympy,sahilshekhawat/sympy,hrashk/sympy,debugger22/sympy,pbrady/sympy,pandeyadarsh/sympy,aktech/sympy,lindsayad/sympy,VaibhavAgarwalVA/sympy,chaffra/sympy,garvitr/sympy,hargup/sympy,maniteja123/sympy,MridulS/sympy,wanglongqi/sympy,pbrady/sympy,Arafatk/sympy,Mitchkoens/sympy,atsao72/sympy,skidzo/sympy,iamutkarshtiwari/sympy,lindsayad/sympy,kevalds51/sympy,lidavidm/sympy,Mitchkoens/sympy,chaffra/sympy,mcdaniel67/sympy,dqnykamp/sympy,emon10005/sympy,farhaanbukhsh/sympy,abhiii5459/sympy,AunShiLord/sympy,maniteja123/sympy,atsao72/sympy,atreyv/sympy,vipulroxx/sympy,cccfran/sympy,jbbskinny/sympy,sahmed95/sympy,sunny94/temp,bukzor/sympy,sampadsaha5/sympy,Titan-C/sympy,jbbskinny/sympy,Davidjohnwilson/sympy,shikil/sympy,farhaanbukhsh/sympy,dqnykamp/sympy,kumarkrishna/sympy,madan96/sympy,flacjacket/sympy,ChristinaZografou/sympy,oliverlee/sympy,mcdaniel67/sympy,AunShiLord/sympy,skidzo/sympy,iamutkarshtiwari/sympy,lidavidm/sympy,postvakje/sympy,beni55/sympy,Arafatk/sympy,sunny94/temp