Symbols defined by gdraps

() <*> <\*> *** && || not elem notElem mappend / separate / escape / *
fix * and / Integer =<< maybe * / set operations

preserve horizontal space for ->, <-, ::

prevent >> match against >>>
Fixes by TheBB
Fix hs_DeclareFunction to not override fundef.

The syn match hs_DeclareFunction was making it impossible to separately
highlight the function definition part of a type signature in an earlier
syntax file.
Add ⇝ , ‼ , ∧ , ∨ , ↠ , ↞ , ∪ , ∩ , ¬ , ×