docs(input[email]): note limitations with IPv6 addresses

Closes #16599

src/ng/directive/input.js

@@ -909,8 +909,10 @@ var inputType = {
    *
    * <div class="alert alert-warning">
    * **Note:** `input[email]` uses a regex to validate email addresses that is derived from the regex
-   * used in Chromium. If you need stricter validation (e.g. requiring a top-level domain), you can
-   * use `ng-pattern` or modify the built-in validators (see the {@link guide/forms Forms guide})
+   * used in Chromium, which may not fulfill your app's requirements.
+   * If you need stricter (e.g. requiring a top-level domain), or more relaxed validation
+   * (e.g. allowing IPv6 address literals) you can use `ng-pattern` or
+   * modify the built-in validators (see the {@link guide/forms Forms guide}).
    * </div>
    *
    * @param {string} ngModel Assignable AngularJS expression to data-bind to.