Added m4sugar language, moved samples to right locations.

lib/linguist/languages.yml

@@ -1917,9 +1917,23 @@ M:
   - .m
   tm_scope: source.lisp
   ace_mode: lisp
-  
+
 M4:
   type: programming
+  aliases:
+  - autoconf
+  extensions:
+  - .m4
+  filenames:
+  - configure.ac
+  tm_scope: none
+  ace_mode: text
+
+M4Sugar:
+  type: programming
+  group: M4
+  aliases:
+  - autoconf
   extensions:
   - .m4
   filenames: