Add a constant for receipt types (m.read). (#11531)

And expand some type hints in the receipts storage module.

1 files changed, 4 insertions, 0 deletions

diff --git a/synapse/api/constants.py b/synapse/api/constants.py

index f7d29b4319..52c083a20b 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -253,5 +253,9 @@ class GuestAccess:
     FORBIDDEN: Final = "forbidden"
 
 
+class ReceiptTypes:
+    READ: Final = "m.read"
+
+
 class ReadReceiptEventFields:
     MSC2285_HIDDEN: Final = "org.matrix.msc2285.hidden"