Provide our own .tmLanguage file to be be able to fix smaller lexer problems.

The fix_syntax.py script checks if the extension is .hs or .hsc, and if so sets the syntax to our syntax file.

Whe start off with the original built-in .tmLanguage as of
https://github.com/cj/sublime/blob/68a5507f11083777d71e3fb00dc5f69880750904/Haskell/Haskell.tmLanguage
tmLanguage: Fix words containing `module` or `where` to break Sublime's lexing.

Also treat .hsc files as Haskell.