docs: convert all @experimental tags to @publicApi tags (#26595)

PR Close #26595

packages/upgrade/src/common/downgrade_component.ts

@@ -56,11 +56,11 @@ interface Thenable<T> {
  * @returns a factory function that can be used to register the component in an
  * AngularJS module.
  *
- * @experimental
+ * @publicApi
  */
 export function downgradeComponent(info: {
   component: Type<any>;
-  /** @experimental */
+  /** @publicApi */
   propagateDigest?: boolean;
   /** @deprecated since v4. This parameter is no longer used */
   inputs?: string[];

packages/upgrade/src/common/downgrade_injectable.ts

@@ -48,7 +48,7 @@ import {INJECTOR_KEY} from './constants';
  * @returns a [factory function](https://docs.angularjs.org/guide/di) that can be
  * used to register the service on an AngularJS module.
  *
- * @experimental
+ * @publicApi
  */
 export function downgradeInjectable(token: any): Function {
   const factory = function(i: Injector) { return i.get(token); };