[DOCS] Fix typo in SLM retention docs (#54797)

Author: chtitux

docs/reference/slm/slm-retention.asciidoc

@@ -6,7 +6,7 @@
 Automatic deletion of older snapshots is an optional feature of snapshot lifecycle management.
 Retention is run as a cluster level task that is not associated with a particular policy's schedule
 (though the configuration of which snapshots to keep is done on a per-policy basis). Retention
-configuration conists of two parts—The first a cluster-level configuration for when retention is
+configuration consists of two parts—The first a cluster-level configuration for when retention is
 run and for how long, the second configured on a policy for which snapshots should be eligible for
 retention.