haXe is now "Haxe"

According to https://groups.google.com/forum/#!topic/haxelang/O7PB-ZrX4i4/discussion

The lexer in Pygments is not renamed yet, so just stay as is at the moment.

lib/linguist/languages.yml

@@ -596,17 +596,6 @@ HTTP:
   type: data
   primary_extension: .http
 
-HaXe:
-  type: programming
-  lexer: haXe
-  ace_mode: haxe
-  color: "#346d51"
-  primary_extension: .hx
-  extensions:
-  - .hx
-  - .hxml
-  - .mtt
-
 Haml:
   group: HTML
   type: markup
@@ -620,6 +609,15 @@ Haskell:
   - .hs
   - .hsc
 
+Haxe:
+  type: programming
+  lexer: haXe
+  ace_mode: haxe
+  color: "#346d51"
+  primary_extension: .hx
+  extensions:
+  - .hxsl
+
 INI:
   type: data
   extensions: