Remove fictitious `token` parameter on `/keys/query` (#1485)

changelogs/client_server/newsfragments/1485.clarification

@@ -0,0 +1 @@
+Remove fictitious `token` parameter on `/keys/query` endpoint

data/api/client-server/keys.yaml

@@ -177,13 +177,6 @@ paths:
                     description: "device ID"
                 example:
                   "@alice:example.com": []
-              token:
-                type: string
-                description: |-
-                  If the client is fetching keys as a result of a device update received
-                  in a sync request, this should be the 'since' token of that sync request,
-                  or any later sync token. This allows the server to ensure its response
-                  contains the keys advertised by the notification in that sync.
             required:
               - device_keys