despite that the "value_status_count" is not rendered/used yet,
it'd be better to keep it in sync with the code.
since 5fd30578d7 added
"Deprecated" to `value_status` enum, let's update the sphinx
extension accordingly.
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes scylladb/scylladb#16236