bug#62508: 28.2; vhdl-mode ModelSim compile warnings aren't highlighted

[Mattias Engdegård]

The new regexp,

"^\\(ERROR\\|WARNING\\|\\*\\* Error\\|\\*\\* Warning\\)[^:]*:\\( *\[[0-9]\]\\| 
([^)]+)\\)? \\([^ \t\n]+\\)(\\([0-9]+\\)):"
                                                                  ^^^^^^^^^

isn't quite right: there are single-escaped square brackets, and the original 
regexp permitted multiple digits, not just one, between square brackets. The 
part

  "\[[0-9]\]"

should probably be

  "\\[[0-9]+]"

but the author needs to confirm this.