minor fixes
minor fixes

fixing link and markup in new section on annotation
Axure/MathJax-docs,Axure/MathJax-docs,mathjax/MathJax-docs,mathjax/MathJax-docs,mitya57/mathjax-docs,mitya57/mathjax-docs,GerHobbelt/MathJax-docs,GerHobbelt/MathJax-docs