docs(core): clarify supported ViewChild selectors (#22784)

PR Close #22784

packages/core/src/metadata/di.ts

@@ -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'}