Git branch outputs usage message on stderr

[Jonas Konrad <jonas.konrad@xxxxxxxxxxxxxxx>]

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,

--
Jonas Konrad, PhD Student
Institute for Geoinformatics, University Münster
Heisenbergstr. 2, 48149 Münster

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