Add a short notice on how to invoke compute_known_facts.
Add a short notice on how to invoke compute_known_facts.

I believe this short notice may be helpful for those who will try to use
compute_known_facts for the first time.

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