Mention callbacks introduced in v1.44.0 and v1.45.0

As per #10898, #10910 and #10894

docs/modules/spam_checker_callbacks.md

@@ -28,6 +28,8 @@ any of the subsequent implementations of this callback.
 
 ### `user_may_join_room`
 
+_First introduced in Synapse v1.37.0_
+
 ```python
 async def user_may_join_room(user: str, room: str, is_invited: bool) -> bool
 ```
@@ -65,6 +67,8 @@ any of the subsequent implementations of this callback.
 
 ### `user_may_send_3pid_invite`
 
+_First introduced in Synapse v1.45.0_
+
 ```python
 async def user_may_send_3pid_invite(
     inviter: str,
@@ -121,6 +125,8 @@ any of the subsequent implementations of this callback.
 
 ### `user_may_create_room_with_invites`
 
+_First introduced in Synapse v1.44.0_
+
 ```python
 async def user_may_create_room_with_invites(
     user: str,