Feature: #63453 - Template support for FlashMessagesViewHelper

See Issue #63453

Description

Template support for FlashMessagesViewHelper has been added. This allows to define a custom rendering for flash messages.

The new attribute as for the FlashMessagesViewHelper allows to specify a variable name, which can be used within the view helper’s child elements to access the flash messages.

Example usage:

<f:flashMessages as="flashMessages">
        <ul class="myFlashMessages">
                <f:for each="{flashMessages}" as="flashMessage">
                        <li class="alert {flashMessage.class}">
                                <h4>{flashMessage.title}</h4>
                                <span class="fancy-icon">{flashMessage.message}</span>
                        </li>
                </f:for>
        </ul>
</f:flashMessages>