Remove trailing commas in function parameter lists

Related issue:
- https://github.com/uBlockOrigin/uBlock-issues/issues/681

dist/version

@@ -1 +1 @@
-1.21.4
+1.21.6

src/js/scriptlet-filtering.js

@@ -396,12 +396,12 @@
         out.unshift(
             '(function() {',
             '// >>>> start of private namespace',
-            '',
+            ''
         );
         out.push(
             '',
             '// <<<< end of private namespace',
-            '})();',
+            '})();'
         );
 
         return out.join('\n');