Katex: Math operators require braces when used in superscript/subscript

[jason-s]

On katex.org, enter T_\max

Resulting behavior:

KaTeX parse error: Got function 'max' with no arguments as subscript at position 3: T_̲m̲a̲x̲

Expected behavior: This should be identical to T_{\max}, which does work fine in KaTeX. The T_\max does work in LaTeX and MathJax: http://jbergknoff.github.io/mathjax-sandbox/#JFRfXG1heCQ%3D

Superscripts and subscripts should not require braces.

[edemaine]

@ylemkimon Will this be fixed by #2085?

[ylemkimon]

This will be fixed by #2085 combined with #2134.

[ylemkimon]

Actually, LaTeX adds the missing brace via error recovery:

Missing { inserted.
leading text: $x_\max

This feature is tracked by #428.