bug#52420: admin/release-branch.txt: move NEWS in single commit

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

>> +  (unless admin-git-command
>> +    (user-error "Could not find git in `exec-path'"))
>
> When this happens, I think admin.el should show instructions for how
> to do that manually, instead of just displaying an error message.

I'm not sure I understand what you mean here.  Could you elaborate?  For
example, what instructions do you think should we show here?