fix font rendering for magit v4.4.0+

[andycandy-dev]

Magit v4.4.0 Compatibility Fix

Problem

After upgrading to Magit v4.4.0, emacs-pr-review lost:

1. Syntax highlighting in diff code blocks
2. Proper fontification of UI elements (titles, mentions, sections, etc.)

Root Cause

Magit v4.4.0 changed from using face text properties to font-lock-face properties for all text rendering in magit-section-mode buffers.

From Magit v4.4.0 changelog:

"All text inserted into Magit buffers that previously used face now use font-lock-face and magit-section-mode can therefore set font-lock-defaults."

fixes #20

ok, I've been fighting my agent for a while now, this seems to legitimately fix fonts on both UI and diff sections.
I've introduced overlays, didn't find a better way to have support for syntax highlighting.
tested with magit@4.4.0 and magit@4.4.2 on doomemacs.

[andycandy-dev]

@blahgeek @gavv can you guys review please?

[blahgeek]

Thank you so much for submitting the issue and the pull request.

I do agree with you that using overlay to support diff section's highlighting does not seem to be the best option, especially for the "post-command-hook" part. I don't know a better way either.

Also, maybe for the similar reason as the diff section, the faces of the HTML body are still missing. (see below. first image is the result of current PR. second image is the expected result)

I do hope we can find a better solution.

Until then, I've pushed a quick fix d893429 to master that set font-lock-defaults back to nil, which should also fix the issue. Though I'm not sure if it's a good fix in the long run.

[andycandy-dev]

the faces of the HTML body are still missing.
missed that, yeah.