message: docs(upgrade): add example links to `downgradeComponent()` function docs
  There were some extra examples for `downgradeComponent()` in the upgrade
  guide. Added a link to the relevant section of the guide in the
  `downgradeComponent()` docs.
  Fixes
  PR Close
diff: @@ -41,6 +41,9 @@ import {LazyModuleRef, UpgradeAppType, controllerKey, getDowngradedModuleCount,
  *
  * {@example upgrade/static/ts/full/module.ts region="ng2-heroes-wrapper"}
  *
  + * For more details and examples on downgrading Angular components to AngularJS components please
  + * visit the [Upgrade guide](guide/upgrade#using-angular-components-from-angularjs-code).
  + *
  * @param info contains information about the Component that is being downgraded:
  *
  * - `component: Type<any>`: The type of the Component that will be downgraded
  