message: docs(core): clarify supported ViewChild selectors
  PR Close
diff: @@ -321,8 +321,21 @@ export interface ViewChildDecorator {
  * * **selector** - the directive type or the name used for querying.
  * * **read** - read a different token from the queried elements.
  *
  + * Supported selectors include:
  + * * any class with the `@Component` or `@Directive` decorator
  + * * a template reference variable as a string (e.g. query `<my-component #cmp></my-component>
  + * with `@ViewChild('cmp')`)
  + * * any provider defined in the child component tree of the current component (e.g.
  + * `@ViewChild(SomeService) someService: SomeService`)
  + * * any provider defined through a string token (e.g. `@ViewChild('someToken') someTokenVal:
  + * any`)
  + * * a `TemplateRef` (e.g. query `<ng-template></ng-template>` with `@ViewChild(TemplateRef)
  + * template;`)
  + *
  * @usageNotes
  *
  + * {@example core/di/ts/viewChild/view_child_example.ts region='Component'}
  + *
  * ### Example
  *
  * {@example core/di/ts/viewChild/view_child_howto.ts region='HowTo'}
  