Consider casing for keyboard shortcuts

[elstoc]

We use a mix of uppercase and lowercase characters to represent keyboard keys. Our contributing guidelines say we should use lowercase, but I'm actually preferring uppercase now, since it matches what's printed on most keyboards.

We should choose one and fix any inconsistencies.

[Phemisters]

since it matches what's printed on most keyboards.

On the other hand, the darktable preferences -> shortcuts use lower case. 🤷 But I agree that we should make the docs internally consistent.

[github-actions]

This issue has not had any activity in the past 60 days and will be closed in 365 days if not updated.

[wildjerry]

Looking at examples of keyboard shortcuts shown online suggests that the standard way is to use capitals, but if we're going to go the trouble of sorting through every keyboard shortcut, we should consider moving to using <kbd> tags, which are meant for this purpose, improving accessibility and readability. For instance <kbd>ctrl</kbd>+<kbd>X</kbd> renders as ctrl+X

The config yaml would need to be modified to allow raw html(see Hugo Docs), but since we aren't rendering untrusted content, that isn't a security risk.

markup:
  highlight:
    style: algol_nu
  tableOfContents:
    endLevel: 3
    ordered: false
    startLevel: 1
  goldmark:
    renderer:
      unsafe: true

Currently, there's an issue where <kbd> tags render in black on black, so that does need to be resolved. I think it's due to the theme we are using, so I'll try to get it fixed upstream.

[elstoc]

Keeping to markdown-only is why we didn't do this

[wildjerry]

Why exactly are we keeping to markdown only? Considering markdown's compatibility with html, I don't think I understand the concern.

[elstoc]

I guess we're trying to keep it simple, which is mostly the point of markdown. Once it becomes markdown+html there's a question of, well why not more html? I'm not sure that <kbd> tags are an essential thing that's lacking from our documentation (IMO it's fine just as fixed width text).

[wildjerry]

Besides improving readability, using keyboard tags also follows semantic tagging guidelines, improving accessibility(screen readers etc. use those tags to give better information to users)