Fix spelling for AMSsymbols (reported by Fred)
Fix spelling for AMSsymbols (reported by Fred)

GerHobbelt/MathJax-docs,mathjax/MathJax-docs,Axure/MathJax-docs,GerHobbelt/MathJax-docs,Axure/MathJax-docs,mitya57/mathjax-docs,mathjax/MathJax-docs,mitya57/mathjax-docs