docs(CONTRIBUTING.md): anachor fix

Closes #7294

Author: ChrisRose

CONTRIBUTING.md

@@ -84,7 +84,7 @@ Before you submit your pull request consider the following guidelines:
 
 * Search [GitHub](https://github.com/angular/angular.js/pulls) for an open or closed Pull Request
   that relates to your submission. You don't want to duplicate effort.
-* Please sign our [Contributor License Agreement (CLA)](#signing-the-cla) before sending pull
+* Please sign our [Contributor License Agreement (CLA)](#cla) before sending pull
   requests. We cannot accept code without this.
 * Make your changes in a new git branch