Display and edit Markdown comments in the Content Editor
Problem to solve
The new content editor introduced in the Wiki provides a rich, visual Markdown editing experience without requiring the underlying file to divert from the Markdown source. This allows Markdown content to continue to be stored, consumed, and edited in many ways across GitLab. One way Markdown files are used is to populate templates, especially issue and epic templates. Frequently, Markdown comments are left in these templates to guide the creation of content without rendering on the final page.
Currently, the content editor does not know what to do with comments.
Proposal
For the MVC, we should render comments using a different type of treatment that makes it clear they are not meant to be displayed on the rendered page. You should be able to type new comments and edit existing comments on the page.
<!--
A comment could look like this
-->
Later iterations
Later iterations could extend this node type and provide alternate UI for comments in the file, potentially moving the contents of the comment into a tooltip or other modal UI and limiting the "canvas" real estate to an icon or something?