Remove 'Haskell (improved) syntax'

.gitmodules

@@ -70,9 +70,6 @@
 [submodule "assets/syntaxes/JavaScript (Babel)"]
 	path = assets/syntaxes/02_Extra/JavaScript (Babel)
 	url = https://github.com/babel/babel-sublime
-[submodule "assets/syntaxes/Cabal"]
-	path = assets/syntaxes/02_Extra/Cabal
-	url = https://github.com/SublimeHaskell/SublimeHaskell
 [submodule "assets/syntaxes/Dart"]
 	path = assets/syntaxes/02_Extra/Dart
 	url = https://github.com/guillermooo/dart-sublime-bundle

assets/README.md

@@ -47,4 +47,5 @@ The following files have been manually modified after converting from a `.tmLang
    https://github.com/seanjames777/SML-Language-Definitiona as it is not
    kept in a standalone repository. The file generated is from
    https://github.com/seanjames777/SML-Language-Definition/blob/master/sml.tmLanguage
-
+* `Cabal.sublime_syntax` has been added manually from
+  https://github.com/SublimeHaskell/SublimeHaskell/ - we don't want to include the whole submodule because it includes other syntaxes ("Haskell improved") as well.