docs: added description for `novalidate` form attribute. (#35166)

PR Close #35166

packages/forms/src/directives/ng_form.ts

@@ -90,6 +90,20 @@ const resolvedPromise = (() => Promise.resolve(null))();
  * </form>
  * ```
  *
+ * ### Native DOM validation UI
+ *
+ * In order to prevent the native DOM form validation UI from interfering with Angular's form
+ * validation, Angular automatically adds the `novalidate` attribute on any `<form>` whenever
+ * `FormModule` or `ReactiveFormModule` are imported into the application.
+ * If you want to explicitly enable native DOM validation UI with Angular forms, you can add the
+ * `ngNativeValidate` attribute to the `<form>` element:
+ *
+ * ```html
+ * <form ngNativeValidate>
+ *   ...
+ * </form>
+ * ```
+ *
  * @ngModule FormsModule
  * @publicApi
  */