Fix titles in schemas

api/server-server/joins.yaml

@@ -81,6 +81,7 @@ paths:
                   depending on the room version - check the `room version specification`_
                   for precise event formats.
                 type: object
+                title: Event Template
                 properties:
                   sender:
                     type: string

api/server-server/leaving.yaml

@@ -73,6 +73,7 @@ paths:
                   depending on the room version - check the `room version specification`_
                   for precise event formats.
                 type: object
+                title: Event Template
                 properties:
                   sender:
                     type: string

api/server-server/third_party_invite.yaml

@@ -85,6 +85,7 @@ paths:
                   third_party_invite:
                     type: object
                     description: The third party invite
+                    title: Third Party Invite
                     properties:
                       display_name:
                         type: string