Allow defining a tagName for InnerBlocks

hey @lgladdy,

Using the ACF <InnerBlocks> tag allow us to set a class name and in combination with add_filter( 'acf/blocks/wrap_frontend_innerblocks', ... ) filter we can output the wrapper div for back end and front end.

But in some cases this leads to wrong semantics.

If my block wrapper tag is a <ul> list, the <InnerBlocks> output wrapper tag is always a <div>. The result is:

<ul class="acf-block-wrapper">
    <div class="acf-inner-blocks-container">block content</div>
    <div class="acf-inner-blocks-container">block content</div>
</ul>

But it should be:

<ul class="acf-block-wrapper">
    <li class="acf-inner-blocks-container">block content</li>
    <li class="acf-inner-blocks-container">block content</li>
</ul>

Is there a way to define a tagName for the <InnerBlocks> tag? Like:

<InnerBlocks tagName="li" class="list-item" />

Start by tracing how the ACF InnerBlocks tag generates its wrapper and how the acf/blocks/wrap_frontend_innerblocks filter affects it. Check the existing InnerBlocks handling before deciding where the requested tagName option belongs. Done means allowing a custom wrapper tag such as li while preserving the class and valid list markup.