Merge pull request #281 from matrix-org/dbkr/fix_meta_escaping

Fix meta-escaping fail

api/client-server/definitions/sync_filter.yaml

@@ -3,7 +3,7 @@ properties:
     description: List of event fields to include. If this list is absent then all
       fields are included. The entries may include '.' charaters to indicate sub-fields.
       So ['content.body'] will include the 'body' field of the 'content' object. A
-      literal '.' character in a field name may be escaped using a '\'. A server may
+      literal '.' character in a field name may be escaped using a '\\'. A server may
       include more fields than were requested.
     items:
       type: string