message: docs(core): change URL to shadow dom spec
  The old URL (https://w3c.github.io/webcomponents/spec/shadow/) is no longer available.
  This commit updates to link to MDN instead.
  Fixes
  PR Close
diff: @@ -40,7 +40,7 @@ export enum ViewEncapsulation {
  * Use Shadow DOM to encapsulate styles.
  *
  * For the DOM this means using modern [Shadow
  - * DOM](https://w3c.github.io/webcomponents/spec/shadow/) and
  + * DOM](https://developer.mozilla.org/en-US/docs/Web/Web_Components/Using_shadow_DOM) and
  * creating a ShadowRoot for Component's Host Element.
  */
  ShadowDom = 3
  