Improved doctest coverage for Tensor.
Improved doctest coverage for Tensor.

Added several examples and documentations where needed in the Tensor module.

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