Documentation: filesystems: caching/operations: drop doubled word

Drop the doubled word "be".
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: David Howells <dhowells@redhat.com>
Cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/20200703214325.31036-3-rdunlap@infradead.orgSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/caching/operations.rst

@@ -27,7 +27,7 @@ data storage and retrieval routines.  Its operations are represented by
 fscache_operation structs, though these are usually embedded into some other
 structure.
 
-This facility is available to and expected to be be used by the cache backends,
+This facility is available to and expected to be used by the cache backends,
 and FS-Cache will create operations and pass them off to the appropriate cache
 backend for completion.