When creating a PR against a selected branch (via O = "create pull request
options"), the user will first be asked to select a remote (if there is more
than one). After that, the suggestion area is populated with all remote branches
at that origin - instead of all local ones. After all, creating a PR against a
branch that doesn't exist on the remote won't work.
Please note that for the "PR is not filed against 'origin' remote" use case
(e.g. when contributing via a fork that is 'origin' to a GitHub project that is
'upstream'), the opened URL will not be correct. This is not a regression and
will be fixed in an upcoming PR.
Fixes#1826.
949e131ebe