Spec implicit filter event limit (#1463)

Signed-off-by: Stuart Mumford <[email protected]>

Author: Cadair

changelogs/client_server/newsfragments/1463.clarification

@@ -0,0 +1 @@
+Clarify that servers should enforce a default `limit` on a filter if one is not specified.

data/api/client-server/definitions/event_filter.yaml

@@ -14,7 +14,11 @@
 title: EventFilter
 properties:
   limit:
-    description: The maximum number of events to return.
+    description: |
+      The maximum number of events to return, must be an integer greater than 0.
+
+      Servers should apply a default value, and impose a maximum value to avoid
+      resource exhaustion.
     type: integer
   not_senders:
     description: A list of sender IDs to exclude. If this list is absent then no senders