adjusted gitignore for adjusted plugin name

.gitignore

@@ -47,7 +47,7 @@
 !/lib/plugins/popularity
 !/lib/plugins/revert
 !/lib/plugins/safefnrecode
-!/lib/plugins/styler
+!/lib/plugins/styling
 !/lib/plugins/testing
 !/lib/plugins/usermanager
 !/lib/plugins/action.php