Don't check comented regions

[zunbeltz]

I am using LanguageTool in LaTeX text. I guess that the integration with AUCTeX will be complicated, but I think that maybe it would be easy to implement the ability to skip commented regions.

[cjl8zf]

@zunbeltz I had the same issue and so I implemented a small package that allows you to tell Langtool to ignore certain regions of text based on their font. I used this effectively to stop Langtool from complaining about stuff in LaTeX math-mode and also LaTeX comments. See here https://github.com/cjl8zf/langtool-ignore-fonts. Perhaps one day this could be added to the Emacs Langtool package. I would love to know what @mhayashi1120 thinks.