rewriting link to config directory to point to github instead of CDN
rewriting link to config directory to point to github instead of CDN

Axure/MathJax-docs,mathjax/MathJax-docs,Axure/MathJax-docs,mathjax/MathJax-docs,GerHobbelt/MathJax-docs,GerHobbelt/MathJax-docs