docs(downloading.ngdoc): remove link to Google CDN overview page

AngularJS is no longer listed on the CDN page, because the available versions
were almost always out of date due to the need to manually update the list

Author: Narretz

docs/content/misc/downloading.ngdoc

@@ -3,8 +3,7 @@
 @description
 
 # Including AngularJS scripts from the Google CDN
-The quickest way to get started is to point your html `<script>` tag to a
-[Google CDN](https://developers.google.com/speed/libraries/#angularjs) URL.
+The quickest way to get started is to point your html `<script>` tag to a Google CDN URL.
 This way, you don't have to download anything or maintain a local copy.
 
 There are two types of AngularJS script URLs you can point to, one for development and one for