markdown fields in revdep_check_failure.yml

[tdhock]

Hi @Keykyrios can you please review?
I used this to file #7770 and I noticed it would be easier if several fields were markdown.

check https://github.com/Rdatatable/data.table/blob/tdhock-revdep-form/.github/ISSUE_TEMPLATE/revdep_check_failure.yml to see if there are errors.

[Keykyrios]

Hi @tdhock, good call making these fields markdown-capable especially for additional-context where @mentions, links, and MREs benefit from formatting.

The main issue is that type: input creates a single-line text field (like <input type="text">), while type: textarea creates a multi-line field (like <textarea>). Switching to input would make it impossible to paste multi-line check output or write detailed context as you saw in #7770, that output is 50+ lines.

The good news is the fix to enable markdown is simpler: just remove the render: text line from check-output. That attribute is what forces content into a raw code block without it, textarea renders as markdown by default. The additional-context field already had no render attribute, so it was already markdown-capable.

So the only change needed from the original template is render: text

Optionally, the description text could guide users to wrap raw check output in a fenced code block (triple backticks), so it stays readable within the markdown-rendered field.

[Keykyrios]

type: input creates a single-line text field, which won't work for the check-output field. Users need to paste multi-line R CMD check output here (as you did in #7770, that output is 50+ lines).

Since render: text is already removed in this PR, the only remaining fix is to revert type back to textarea, that will give multi-line support and markdown rendering.

[Keykyrios]

Same issue here type: input is single-line. This field is where users include MREs, multiple links, @mentions, etc. which are inherently multi-line. Should remain textarea.

[Keykyrios]

Since the field will now render as markdown, it might be helpful to suggest users wrap their check output in a fenced code block so it doesn't render as broken markdown. Maybe something like:

Describe the relevant R CMD check output showing the failure. Paste check output inside a fenced code block (triple backticks).

This way users get the best of both worlds, they can write markdown context around the check output while the output itself stays readable