Remove distinction between StateFilter and RoomEventFilter (#2015)

They are exactly the same type, so let's combine their tables together.

data/api/client-server/definitions/sync_filter.yaml

@@ -69,7 +69,6 @@ properties:
         type: boolean
       state:
         type: object
-        title: StateFilter
         allOf:
         - $ref: room_event_filter.yaml
         description: The state events to include for rooms.

data/api/client-server/sync.yaml

@@ -26,7 +26,8 @@ paths:
         incremental deltas to the state, and to receive new messages.
 
         *Note*: This endpoint supports lazy-loading. See [Filtering](/client-server-api/#filtering)
-        for more information. Lazy-loading members is only supported on a `StateFilter`
+        for more information. Lazy-loading members is only supported on the `state` part of a
+        [`RoomFilter`](#post_matrixclientv3useruseridfilter_request_roomfilter)
         for this endpoint. When lazy-loading is enabled, servers MUST include the
         syncing user's own membership event when they join a room, or when the
         full state of rooms is requested, to aid discovering the user's avatar &