IGNITE-28646 Add description of '--cancel' flag for idle_verify command (#13165)

Author: DenisPolo

docs/_docs/tools/control-script.adoc

@@ -689,6 +689,13 @@ Partition instances: [PartitionHashRecord [isPrimary=true, partHash=97595430, up
 All updates should be stopped when `idle_verify` calculates hashes, otherwise it may show false positive error results. It's impossible to compare big datasets in a distributed system if they are being constantly updated​.
 ====
 
+To cancel a running `idle_verify` operation, use the `--cancel` argument:
+
+[source, shell]
+----
+control.sh --cache idle_verify --cancel
+----
+
 === Repairing cache consistency
 [WARNING]
 ====