Last button in component doc example not vertically aligned correctly

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

The last buttons are not vertically aligned with the other buttons in a same row in the examples.

It may be caused by the increase of the selector specificity defined in https://github.com/twbs/bootstrap/commit/37f3977e6d96e274cb73255d99e3e4ec60f03c0f:

> :not(hr):last-child {
  margin-bottom: 0;
}

Reduced test cases

The issue can be directly observed in the /docs/5.1/components/buttons/ on the actual main branch.

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

macOS, Linux

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

Firefox

What version of Bootstrap are you using?

v5.2.0 (current main branch)