doc: fix typo in PGP guide

Fix typo in the GPG guide for maintainers
Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/process/maintainer-pgp-guide.rst

@@ -943,7 +943,7 @@ have on your keyring::
 
 Next, open the `PGP pathfinder`_. In the "From" field, paste the key
 fingerprint of Linus Torvalds from the output above. In the "To" field,
-paste they key-id you found via ``gpg --search`` of the unknown key, and
+paste the key-id you found via ``gpg --search`` of the unknown key, and
 check the results:
 
 - `Finding paths to Linus`_