utilities/iterables: Added references to docstrings.
utilities/iterables: Added references to docstrings.

Signed-off-by: Saptarshi Mandal <13ec3c7bab52575f3a0cda6406c76269cc13b041@gmail.com>

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