Merge pull request #1341 from matrix-org/dbkr/add_read_receipt_example

Add example read receipt to sync example

changelogs/client_server/newsfragments/1341.clarification

@@ -0,0 +1 @@
+Add example read receipt to `GET /_matrix/client/v3/sync` response example.

data/api/client-server/sync.yaml

@@ -444,7 +444,8 @@ paths:
                       },
                       "ephemeral": {
                         "events": [
-                          {"$ref": "../../event-schemas/examples/m.typing.yaml"}
+                          {"$ref": "../../event-schemas/examples/m.typing.yaml"},
+                          {"$ref": "../../event-schemas/examples/m.receipt.yaml"}
                         ]
                       },
                       "account_data": {