feat: add lint support for .peggy

Author: zdm

lib/lint/file.js

@@ -99,7 +99,7 @@ customMime.add( {
 } );
 
 customMime.add( {
-    "essence": "application/x-peggy",
+    "essence": "text/x-peggy",
     "compressible": true,
     "extnames": [ ".peggy" ],
 } );