fix: header html tag for monobackgroundcolor + monoforegroundcolor option

[mcanouil]

This PR:

• fix: add h1-6 tags to the CSS rules to apply monobackgroundcolor on.
  Fixes monobackgroundcolor ignored by document title and section title #6781
• feat: add monoforegroundcolor option.
  Fixes Add option for changing inline code color #6780

This PR accounts for the comment made on #6782 and do not run quarto build-js to avoid merge conflicts.
It also integrates #6785 to ease review as the two are heavily related.
Also this PR ensure it is up to date with main which had a lot of commits recently.

Note that quarto build-js was not executed to avoid conflicts, thus it will be required on merge.

---

---
title: "Document title with `code`"
format:
  html:
    monobackgroundcolor: "transparent"
    monoforegroundcolor: "#b22222"
---

# Section title with `code`

Some text with `code`

[cderv]

This files is directly from Pandoc templates (https://github.com/jgm/pandoc/blob/49e64c1451b9933a025d059f7dae287788c7d1cc/data/templates/styles.html), and monobackgroundcolor is one of Pandoc's variable for HTML (https://pandoc.org/MANUAL.html#variables-for-html)

monoforegroundcolor is not. So it will require to patch the file at each update.

Also this part of the style file is used only when document-css variables is activated. I believe this is only with theme: pandoc in Quarto.

Do we really want to add this monoforegroundcolor support for non bootstrap document ?

If we think this is desired, I think we should do a PR or feature request in Pandoc to add it there for future version (so that no patch is needed on our side)

[mcanouil]

Indeed, this was why at first it was two PRs to get reviews.
This PRs mostly serves as a discussion point for this.

[cscheid]

Thank you!

[cscheid]

Ooof, I'm sorry. I made a mess here. I was looking to merge your schema PR and must have accidentally clicked the wrong button.

[mcanouil]

Is it worth to make a new PR? It's very old (September 2023) and, you know, time is limited^^
I've reopened the issue:

• monobackgroundcolor ignored by document title and section title #6781

[cscheid]

I think we need to address Christophe's concerns before merging a PR to solve the issue. So we don't need to reopen this one right away, and we have your proposal as a point of discussion like you mention. Thanks, and sorry for the confusion again.