Current settings use Python lexer for Nim files, however Lexilla already has a [lexer for Nim](https://github.com/ScintillaOrg/lexilla/blob/master/lexers/LexNim.cxx). This requires an additional PR, but I don't know the process of incorporating scintilla/lexilla updates Geany uses, so, please, advice.
With Python lexer multiline comments (and, perhaps, something else) don't work.