Documentation: filesystems: directory-locking: drop doubled word

Drop the doubled word "the".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20200703214325.31036-5-rdunlap@infradead.org


Signed-off-by: Jonathan Corbet <corbet@lwn.net>