bug#35368: [PATCH v3] Do potentially destructive operations in prepare-commit-msg

[npostavs]

Konstantin Kharlamov <Hi-Angel@yandex.ru> writes:

> * build-aux/git-hooks/prepare-commit-msg: if someone occasionally puts
> Signed-off line, it will likely get there through -s option of git.
> Exploit this fact to abort before a user got a chance to type commit
> message.

Thanks, looks good, but I think it would be helpful to explain that this
is about catching git commit -s ... in the comments of the file too.

> --- a/autogen.sh
> +++ b/autogen.sh
> @@ -1,4 +1,4 @@
> -#!/bin/sh
> + #!/bin/sh

This is a typo or something, right?