Add hooks to integrate with Action Text

[seanpdoyle]

One major challenge that applications face when integrating with morphing-powered Page Refreshes involves <trix-editor> elements rendered by Action Text.

The emergent guidance instructs applications to skip morphing by marking the <trix-editor> as permanent. This guidance, while correct, does not encapsulate the entire story. In the case of Action Text-rendered <trix-editor> elements, applications might invoke form.rich_text_area with data: {turbo_permanent: true}, expecting for the presence of trix-editor[data-turbo-permanent] to be sufficient.

However, to achieve the intended behavior, applications must nest their <trix-editor> elements within an element with [data-turbo-permanent] (a <div>, a <fieldset>, etc.). This provides a container for the trix-editor to inject its associated <input> and <trix-toolbar> elements. A <trix-editor> element will insert an <input type="hidden"> element and a <trix-toolbar> element when they are absent on connect.

Applications can skip a Trix-manage injection by rendering those either (or both) elements ahead of time, then associating them to the trix-editor through [input] and [toolbar] attributes (respectively).

Action Text skips the <input> injection step by rendering and associating an Action View-rendered <input type="hidden"> attribute with the appropriate attributes.

No matter how the <input> connects to the document, it's important for it to keep its [data-turbo-permanent] synchronized with the trix-editor's attribute in order to tolerate a morph.

Since Page Refreshes, Morphing, and permanence are all Turbo concepts, and Action Text is a Rails framework, turbo-rails feels like the most appropriate codebase (out of rails, trix, turbo, and turbo-rails) to house the integration.