Update description of pending requests metric (#4443)

Co-authored-by: Brian MacDonald <brian.macdonald@temporal.io>

Author: GSmithApps

docs/cloud/metrics/openmetrics/metrics-reference.mdx

@@ -104,7 +104,7 @@ gRPC errors per second.
 
 #### temporal\_cloud\_v1\_service\_pending\_requests
 
-The number of pollers that are waiting for a task. Use this to track against ``temporal_cloud_v1_poller_limit``
+The number of pollers that are actively long polling for a task. Use this to track against ``temporal_cloud_v1_poller_limit``
 
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