Fix bug from roomuserid_knockedcount vs. roomid_knockedcount.

The use of "count" instead of "sequence" leads to confusion with
i.e. counting the elements of a set e.g. Iterator::count().

Signed-off-by: Jason Volk <jason@zemos.net>

src/database/maps.rs

@@ -141,6 +141,10 @@ pub(super) static MAPS: &[Descriptor] = &[
 		name: "referencedevents",
 		..descriptor::RANDOM
 	},
+	Descriptor {
+		name: "roomid_knockedcount",
+		..descriptor::RANDOM_SMALL
+	},
 	Descriptor {
 		name: "roomid_invitedcount",
 		..descriptor::RANDOM_SMALL