Add syntax highlighting for Haskell

highlights.scm is copied direct from the nvim-treesitter repository with the latest commit that touched it being 188b1a6d01fd9bcf04bf2bc932d611809b154acc.

Author: Albin a12l Otterhäll

data/config.toml

@@ -144,6 +144,9 @@ lsp.roots = ["melos.yaml", "pubspec.yaml"]
 [filetypes.graphql]
 extensions = ["graphql"]
 
+[filetypes.haskell]
+extensions = ["hs"]
+
 [filetypes.json]
 extensions = ["json"]
 

data/config_tests/valid-ftypes.toml

@@ -12,6 +12,9 @@ lsp.roots = ["melos.yaml", "pubspec.yaml"]
 [graphql]
 extensions = ["graphql"]
 
+[haskell]
+extensions = ["hs"]
+
 [json]
 extensions = ["json"]
 

data/config_tests/valid/all-inline.toml

@@ -79,6 +79,9 @@ lsp.roots = ["melos.yaml", "pubspec.yaml"]
 [filetypes.graphql]
 extensions = ["graphql"]
 
+[filetypes.haskell]
+extensions = ["hs"]
+
 [filetypes.json]
 extensions = ["json"]
 

data/lib/ftype-comment-chars.txt

@@ -2,6 +2,7 @@ bash #
 c //
 dart //
 graphql #
+haskell --
 just #
 make #
 plumbingrules #