updated hsType syntax matching in syntax.vim

- added matching for type signatures that end with ticks
  e.g. b' :: a -> a
- fixes dag#92

Author: sbdchd

autoload/vim2hs/haskell/syntax.vim

@@ -103,7 +103,7 @@ endfunction " }}}
 
 function! vim2hs#haskell#syntax#types() " {{{
   syntax match hsType
-    \ "^\(\s*\)\%(default\s\+\)\?\%(\k\+\|([^[:alnum:]]\+)\)\_s*\(::\|∷\).*\%(\n\1\s.*\)*"
+    \ "^\(\s*\)\%(default\s\+\)\?\%(\k\+\|([^[:alnum:]]\+)\)'*\_s*\(::\|∷\).*\%(\n\1\s.*\)*"
     \ contains=TOP,@Spell
 
   highlight default link hsType Type