Fix typo in Manila docs in manila.rst file
Line 911 : Filer => Filter
Closes-bug:
@@ -899,7 +899,7 @@ List NAS shares with filters.
OPTIONAL: Default=None.
``--snapshot <snapshot>``
- Filer results by snapshot name or id, that was used
+ Filter results by snapshot name or id, that was used
for share.
``--host <host>``
