[lib] Subheadings in class descriptions

[jensmaurer]

We have both:

• Class template blah
  -- blah constructors
  (etc)

and

• Class template blah
  -- Construction and assignment [note: omitting "blah" in subordinate headings]
  (etc)

[basic.string] is an example for the former, [string.view.template] is an example for the latter.

Which way is the "right" way?

[jensmaurer]

Editorial meeting consensus: Do not repeat a parent heading item in subordinate headings.

[tkoeppe]

@jensmaurer: What about [container.node]?

[jensmaurer]

@tkoeppe: [container.node] is odd. It specifies an exposition-only class node_handle, which need not exist under this name. Everywhere else in the vicinity, we specify requirements on classes or class templates by specifying the valid operations on them, instead of showing a class synopsis.

I'd like to point out that the superordinate heading says "Node handles" and the subordinate headings say "node_handle", which is not exactly a repetition (although quite close).

[tkoeppe]

@jensmaurer: Yeah, that's true. Not sure what to do here. @zygoloid: Opinions?

My primary goal here is to get rid of a bold-italic-teletype font requirement, which we cannot satisfy :-)