Git branch outputs usage message on stderr

Hey, please find the report below.

What did you do before the bug happened? (Steps to reproduce your issue) I opened a terminal on Arch Linux with a bash shell and called `git branch -h` to get a usage overview of git's `branch` command. I then tried processing the output with `grep` by `git branch -h | grep list` which gave the whole (unfiltered) output, i.e., the displayed message was not processed by `grep`.

What did you expect to happen? (Expected behavior) Pipe redirects stdout to grep (here: usage info of git branch) and grep can filter it.

What happened instead? (Actual behavior) `git branch -h` output was not redirected to `grep`. Instead, it went to stderr, bypassing the pipe. Using `|&` as pipe gives the expected result and confirms that the usage output is indeed redirected to stderr.

What's different between what you expected and what actually happened? To me, `git branch -h` (invoked without any non-valid option) shall output its help/usage message to stdout, and exit without error status (exit status 0).

Anything else you want to add: In fact, `git branch -h` exits with a non-zero status. This is coherent with outputting the usage message on stderr and made me think the behavior could be intended. I can hardly imagine, as outputting usage info to stderr to me only made sense if `git branch` is invoked with, e.g., a non-valid option (if at all). I would prefer the usage output on stderr even in this case, but allow for a non-zero exit status of git branch. Also, `git -h` gives its output on stdout.

[System Info]
git version:
git version 2.48.1
cpu: x86_64
no commit associated with this build
sizeof-long: 8
sizeof-size_t: 8
shell-path: /bin/sh
libcurl: 8.11.1
OpenSSL: OpenSSL 3.4.0 22 Oct 2024
zlib: 1.3.1
uname: Linux 6.12.8-arch1-1 #1 SMP PREEMPT_DYNAMIC Thu, 02 Jan 2025 
22:52:26 +0000 x86_64
compiler info: gnuc: 14.2
libc info: glibc: 2.40
$SHELL (typically, interactive shell): /bin/bash

Best,