Merge pull request #529 from webcomponents/new-file-license-header

Add a license header to a new file in Shady DOM.

Author: bicknellr

packages/shadydom/src/selector-parser.js

@@ -1,3 +1,9 @@
+/**
+ * @license
+ * Copyright (c) 2022 The Polymer Project Authors
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
 /**
  * A map describing parentheses-like grouping characters and their behavior. The
  * keys are the group's start character and the value's `end` property contains