Documentation: smooth the text flow in the security bug reporting process

Documentation: smooth the text flow in the security bug reporting process

The text was presenting the team, the the e-mail address, then some of
the expectations, then what form of e-mail is expected. By switching
the e-mail paragraph two paragraphs later and dropping the "Contact"
sub-section, we can have a more natural flow that presents the team,
then its expectation, then how to best contribute, then where to send.

And more importantly, it increases the chances that reporters have read
the prerequisites before finding the e-mail address.

Signed-off-by: Willy Tarreau <w@1wt.eu>
Reviewed-by: Kees Cook <kees@kernel.org>
Link: https://lore.kernel.org/r/20250814192730.19252-2-w@1wt.eu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>