Update docs/monitoring/sharding.md

Co-authored-by: Théo Brigitte <[email protected]>

docs/monitoring/sharding.md

@@ -1,6 +1,6 @@
 # Prometheus Agent Sharding
 
-To be able to ingest metrics without disrupting the workload running in the clusters, the observability operator decides on the number of running __prometheus agent shards__ for each workload cluster based . The number of shards depends on the __total number of time series__ stored for a given cluster.
+To be able to ingest metrics without disrupting the workload running in the clusters, the observability operator chooses the number of running __prometheus agent shards__ on each workload cluster. The number of shards is based on the __total number of time series__ ingested for a given cluster.
 
 __By default__, the operator configures a shard for every 1M time series present in Mimir for the workload cluster. To avoid scaling down too abruptly, we defined a scale down threshold of 20%.