Update type annotations for compatiblity with prometheus_client 0.14 (#12389)

Principally, `prometheus_client.REGISTRY.register` now requires its argument to
extend `prometheus_client.Collector`.

Additionally, `Gauge.set` is now annotated so that passing `Optional[int]`
causes an error.

1 files changed, 1 insertions, 3 deletions

diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py

index d253243125..57489c30f1 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -200,9 +200,7 @@ class PersistEventsStore:
             if stream < 0:
                 # backfilled events have negative stream orderings, so we don't
                 # want to set the event_persisted_position to that.
-                synapse.metrics.event_persisted_position.set(
-                    events_and_contexts[-1][0].internal_metadata.stream_ordering
-                )
+                synapse.metrics.event_persisted_position.set(stream)
 
             for event, context in events_and_contexts:
                 if context.app_service: