Darkmode: btn-outline-dark is not visible in button group component

[teaca-sebastian]

Prerequisites

• I have searched for duplicate or closed issues
• I have validated any HTML to avoid common problems
• I have read the contributing guidelines

Describe the issue

https://getbootstrap.com/docs/5.3/components/button-group/#sizing
https://getbootstrap.com/docs/5.3/components/buttons/

The bug is pretty self-explainatory, this happens because .btn-light .btn-dark .btn-outline-light & .btn-outline-dark don't change with data-bs-theme="dark", and there is no "body" color to change along with the data attribute. To properly solve this issue .btn-body and .btn-outline-body classes should be added to complement the darkmode feature.

Reduced test cases

See above

What operating system(s) are you seeing the problem on?

Windows

What browser(s) are you seeing the problem on?

No response

What version of Bootstrap are you using?

v5.3

[julien-deramond]

FYI case 2 is a duplicate of #37711. It can be removed from your description. However I don't think case 1 has already been mentioned somewhere. Thanks for that @teaca-sebastian

[threehymns]

@mdo, for the purposes of other sites using bootstrap, we should still add something like .btn-outline-body and .btn-body for buttons with neutral colors that adapt to dark mode. I honestly don't like those tag names much as they sound too generic because the body part does not sound like a color, so I might suggest something like .btn-outline-monochrome or .btn-monochrome. It would be great if someone could find a better name for these potential components.