Describe the feature or problem you’d like to solve

In the default setting one needs to omit pr, which is confusing (because it is not consistent why one needs to write checkout in one place and co in another place although both terms have the same effect)

$ gh pr co 13280
unknown command "co" for "gh pr"
$ gh co 13280
remote: Enumerating objects: 178, done.

Proposed solution

gh pr co 13280

working

This fullfils IMHO conformity with user expectations.

Additional context

This is a follow-up of #1303