Improved programming languages regular expression

Fixed regular expression to match some languages:
  * '+' ie C++
  * '#' ie C#, F#
  * ' ' ie Game Maker Language
  * '(', ')' for Graphviz (DOT)

It should match now all languages from [linguist/languages.yml](https://github.com/github/linguist/blob/master/lib/linguist/languages.yml)