docs: Fix conflicting contributor identity info

docs: Fix conflicting contributor identity info

In commit d4563201f33a ("Documentation: simplify and clarify DCO
contribution example language"), the patch submission documentation was
updated to remove the note about pseudonyms and instead simplify it to
allow "known identities".

The process documentation still explicitly prohibits pseudonymous
contributors. This patch changes the process documentation to line up
with the submitting patches document.

Signed-off-by: Ammar Askar <ammar@ammaraskar.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250318235331.3566174-1-ammar@ammaraskar.com