Omit all "maint" branch. It is the opposite of -R that omits release
branches.
In other words, -M can be used to list all release branches.
Signed-off-by: David Goulet <dgoulet@torproject.org>
When talking about the "master" Tor checkout, we now refer to it as "the
primary Tor repository". The "master" branch is instead called "main".
See: tpo/core/team#2.
This reverts commit a63b414822.
The "typo" wasn't actually a typo. The "r" in the suffixes for the
release branches is meant to make them distinct from the maint
branches.
Now, _right now_, nothing uses release branch suffixes, but it's
important to keep them distinct if we decide to use them in the
future.
