[flat.map, flat.multimap, flat.set, flat.multiset] Exposition-only formatting for c, comp, compare, and key-equiv

[frederick-vs-ja]

Also changes key_equiv to key-equiv.

I think it's OK to keep the member comp of key_equiv not marked \exposid, since the identifier comp is already reserved by priority_queue::comp. Implementations can use the name comp as-is or use another name.

key_equiv and value_compare's exposition-only constructors are less than ideal to me. But I think they should be handled in an LWG issue because additional copy of comparator seems to be observable. Edit: now this is LWG3959.

Follows up #5914. Fixes #5812. Fixes #7380.

[tkoeppe]

Thank you, this would be quite nice to land. @Dani-Hub, @CaseyCarter, would you perhaps be able to lend another pair of eyes?

[tkoeppe]

@frederick-vs-ja Could you perhaps retrigger the precommit checks so we can get a downloadable PDF?

[Dani-Hub]

Thank you, this would be quite nice to land. @Dani-Hub, @CaseyCarter, would you perhaps be able to lend another pair of eyes?

I would happily do so, but I'm away during from an 30 minutes from now until Tuesday and I'm unable to do that right now.

[frederick-vs-ja]

@frederick-vs-ja Could you perhaps retrigger the precommit checks so we can get a downloadable PDF?

I've rebased and force-pushed, not sure whether this is sufficent...

[Dani-Hub]

The changes look good to me, but I'd like to point out that similar fixes in e.g. for c and compare in [flat.multiset.modifiers] have not been applied. The issue says that it does only touch [flat.map] and [flat.multimap], so this is formally OK.

[tkoeppe]

@Dani-Hub Thanks! Yes, good point, we should fix those cases, too.

[frederick-vs-ja]

@Dani-Hub @tkoeppe Sorry for noticing the comments so late. Now the changes are also applied to [flat.multiset.modifiers].

[Dani-Hub]

@Dani-Hub @tkoeppe Sorry for noticing the comments so late. Now the changes are also applied to [flat.multiset.modifiers].

Looks good to me - Thanks!

[frederick-vs-ja]

Rebased & force-pushed to resolve some conflicts.

[jensmaurer]

Feels like an improvement.

@jwakely , what do you think?

[tkoeppe]

Yes, I like it, this has been a long-standing issue. Thanks!