Undocumented xbps-src commands

[ericonr]

These commands aren't in the help output. They should be removed or documented:

• remove-destdir (seems to be the same as remove, so I'd consider removing)
• show-pkg-var-dump
• show-pkg-var
• dbulk-dump

[Duncaen]

I don't think each of those commands need to be documented in the help/usage, its already pretty big and there is no point in knowing dbulk-dump from a users perspective who is not trying to build tooling around xbps-src.
Same goes for the show-pkg-var they do the same thing as dbulk-dump but with a "looser" output format.

remove-destdir looks like just an alias for remove, I don't see the harm in keeping it for compatibility.

[ericonr]

I'm ok with keeping remove-destdir, but for the others it helps to have usage information as well as what the command does without having to read and understand code. Also helps with discoverability...

[github-actions]

Issues become stale 90 days after last activity and are closed 14 days after that. If this issue is still relevant bump it or assign it.