refactor: add lint text/plain filenames

Author: zdm

lib/lint/file.js

@@ -52,6 +52,14 @@ customMime.get( "application/node" ).shebangs.add( [
     "#!/usr/bin/env node",
 ] );
 
+customMime.get( "text/plain" ).filenames.add( [
+
+    //
+    ".editorconfig",
+    ".gitattributes",
+    ".npmrc",
+] );
+
 customMime.get( "application/x-sh" ).filenames.add( [
 
     //