Rendering the underscore in the online documentation

[hurak]

In the documentation in the section with an example on Lyapunov function search (but perhaps also elsewhere) I encountered a possibly confusing LaTeX-based math rendering. Namely, when an underscore is followed by a left square bracket: _[. For example, right after the code

@variable(model, V, Poly(monos))

Obviosly the underlying LaTeX rendering engine interprets the underscore preceeding the left square bracket as a command to render the bracket as a lower index.