From: "Clarence \"Sparr\" Risher" <sparr0@gmail.com>

`git branch -m` has an optional first argument, the branch to rename.
If omitted, it defaults to the current branch. This behavior is not
currently described in the documentation. While it can be determined
relatively easily through experimentation, and less so through viewing
the source code (builtin/branch.c:897), it is not obvious what such a
command will do when encountered in a less interactive context.

This patch adds one sentence to the git-branch documentation, with
wording based on another optional argument described earlier in the
same doc.

The same behavior applies to -M, -c, and -C, which are all covered by
this same section of the documentation.

Signed-off-by: Clarence Risher <clarence@kira-learning.com>
Signed-off-by: Clarence "Sparr" Risher <sparr0@gmail.com>

Submitted-As: https://lore.kernel.org/git/pull.1613.git.git.1701303891791.gitgitgadget@gmail.com