Apply list group numbering to all items

[chefarbeiter]

I have a list group for which I have enabled numbering with list-group-numbered. This works fine. Then I had to change the list to buttons and in the process the numbering of the entries disappeared. See this example.

A quick look in the code revealed that numbering is only enabled for li elements:

bootstrap/scss/_list-group.scss

Lines 19 to 23 in d3babf7

	> li::before {
	// Increments only this instance of the section counter
	content: counters(section, ".") ". ";
	counter-increment: section;
	}

I think this came about because the numbering in #33068 was initially only for ol elements, but then changed to an opt-in class. However, the restriction to li elements was not removed.

In this PR, I changed the selector to the list-group-item class. This applies the numbering to all possible children of a list group, whether li, button, a or label.

[ffoodd]

Makes sense, thanks!