feat(language-service): Show documentation on hover (#34506)

This commit adds dpcumentation to the hover tooltip.

PR closes https://github.com/angular/vscode-ng-language-service/issues/321

PR Close #34506

packages/language-service/test/project/app/parsing-cases.ts

@@ -132,6 +132,9 @@ export class AsyncForUsingComponent {
 export class References {
 }
 
+/**
+ * This Component provides the `test-comp` selector.
+ */
 /*BeginTestComponent*/ @Component({
   selector: 'test-comp',
   template: '<div>Testing: {{name}}</div>',
@@ -145,6 +148,9 @@ export class TestComponent {
   templateUrl: 'test.ng',
 })
 export class TemplateReference {
+  /**
+   * This is the title of the `TemplateReference` Component.
+   */
   title = 'Some title';
   hero: Hero = {id: 1, name: 'Windstorm'};
   heroes: Hero[] = [this.hero];