message: docs: add example links to 'DoCheck' lifeycle hook docs
  There were some examples for 'DoCheck' in the lifeCycle hooks guide. Added a link to the relevant section of the guide in the 'DoCheck()' api docs.
  Fixes
  PR Close
diff: @@ -86,6 +86,9 @@ export interface OnInit {
  *
  * {@example core/ts/metadata/lifecycle_hooks_spec.ts region='DoCheck'}
  *
  + * For a more complete example and discussion, see
  + * [Defining custom change detection](guide/lifecycle-hooks#defining-custom-change-detection).
  + *
  * @publicApi
  */
  export interface DoCheck {
  