[pyupgrade] `synapse/` (#10348)

This PR is tantamount to running 
```
pyupgrade --py36-plus --keep-percent-format `find synapse/ -type f -name "*.py"`
```

Part of #9744

1 files changed, 1 insertions, 2 deletions

diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py

index 4455fa71a8..3a14260752 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -137,8 +137,7 @@ class _Collector:
             _background_process_db_txn_duration,
             _background_process_db_sched_duration,
         ):
-            for r in m.collect():
-                yield r
+            yield from m.collect()
 
 
 REGISTRY.register(_Collector())