Many templates serve merely as wrapper around free-form wikitext content. TemplateData specifies the parameter type "content" for this purpose.
This task tracks the implementation in VisualEditor to provide an edit surface for editing the values of these parameter. Similar to how we already support rich editing of the content inside References.
Use cases:
- Wrap-templates. Such as message boxes, and the parameter-consuming variants of the "something-start"/"something-end" templates.
- Nested infoboxes.
- Simple infobox fields that support text but allow/encourage use of inline templates for formatting. Currently these expose raw wikitext to end-users.