Remove unspecced DELETE endpoint that modifies room visibility

changelog.d/13123.removal

@@ -0,0 +1 @@
+Remove the unspecced `DELETE /directory/list/room/{roomId}` endpoint, which hid rooms from the [public room directory](https://spec.matrix.org/v1.3/client-server-api/#listing-rooms). Instead, `PUT` to the same URL with a visibility of `"private"`.

synapse/rest/client/directory.py

@@ -151,17 +151,6 @@ async def on_PUT(
 
         return 200, {}
 
-    async def on_DELETE(
-        self, request: SynapseRequest, room_id: str
-    ) -> Tuple[int, JsonDict]:
-        requester = await self.auth.get_user_by_req(request)
-
-        await self.directory_handler.edit_published_room_list(
-            requester, room_id, "private"
-        )
-
-        return 200, {}
-
 
 class ClientAppserviceDirectoryListServer(RestServlet):
     PATTERNS = client_patterns(