opam repo show <repo-name>

[kit-ty-kate]

The output of opam repo list currently is just UI for reading.
However, for example, if you're trying to make sure that a repository of a certain name is attached to the right url, it becomes a bit more complicated than it should.

opam repo list --short doesn't really help as it only shows the names of the repository, not its url or rank, and there is no opam repo show <repo-name> to actually show what rank and url said repository has.

The proposal would be to add an opam repo show <repo-name> command which would look like this:

$ opam repo show default
url: https://opam.ocaml.org
rank: 1

This way would at least be relatively easy to get information about every repositories as it currently looks like the unpalatable:

opam repo list 2> /dev/null | grep "^ [1-9][0-9]* default " | tr -s ' ' | cut -s '-d ' -f4

In the future, the output could also be extended with information like last-modified (see #5553)