Remove distinction between `StateFilter` and `RoomEventFilter` (#2015)

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

changelogs/client_server/newsfragments/2015.clarification

@@ -0,0 +1 @@
+Remove distinction between `StateFilter` and `RoomEventFilter`.

content/client-server-api/_index.md

@@ -1756,8 +1756,9 @@ events to the client to ease implementation, although such redundancy
 should be minimised where possible to conserve bandwidth.
 
 In terms of filters, lazy-loading is enabled by enabling
-`lazy_load_members` on a `RoomEventFilter` (or a `StateFilter` in the
-case of `/sync` only). When enabled, lazy-loading aware endpoints (see
+`lazy_load_members` on a
+[`RoomEventFilter`](#post_matrixclientv3useruseridfilter_request_roomeventfilter).
+When enabled, lazy-loading aware endpoints (see
 below) will only include membership events for the `sender` of events
 being included in the response. For example, if a client makes a `/sync`
 request with lazy-loading enabled, the server will only return

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 &