Changed the use of pyglet Plot module
Changed the use of pyglet Plot module

This example uses, as of now, the old pyglet plotting module
which is not working right now.
My fix uses matplotlib as suggested by @moorepants.
Fixes #10243

aktech/sympy,jerli/sympy,lindsayad/sympy,oliverlee/sympy,hargup/sympy,Titan-C/sympy,kaichogami/sympy,Curious72/sympy,ChristinaZografou/sympy,rahuldan/sympy,drufat/sympy,mafiya69/sympy,rahuldan/sympy,drufat/sympy,kaichogami/sympy,Titan-C/sympy,chaffra/sympy,skidzo/sympy,postvakje/sympy,Titan-C/sympy,Shaswat27/sympy,Curious72/sympy,mafiya69/sympy,ChristinaZografou/sympy,kaushik94/sympy,sampadsaha5/sympy,drufat/sympy,mafiya69/sympy,Shaswat27/sympy,Arafatk/sympy,jaimahajan1997/sympy,postvakje/sympy,aktech/sympy,oliverlee/sympy,chaffra/sympy,madan96/sympy,postvakje/sympy,jaimahajan1997/sympy,rahuldan/sympy,madan96/sympy,Arafatk/sympy,madan96/sympy,yashsharan/sympy,aktech/sympy,lindsayad/sympy,oliverlee/sympy,skidzo/sympy,sampadsaha5/sympy,sampadsaha5/sympy,hargup/sympy,jerli/sympy,chaffra/sympy,Curious72/sympy,yashsharan/sympy,jerli/sympy,souravsingh/sympy,skidzo/sympy,hargup/sympy,lindsayad/sympy,yashsharan/sympy,Shaswat27/sympy,kaichogami/sympy,kaushik94/sympy,Arafatk/sympy,jaimahajan1997/sympy,souravsingh/sympy,souravsingh/sympy,ChristinaZografou/sympy,kaushik94/sympy