rabbitmq-diagnostics(8): wording

(cherry picked from commit 37fbc13)

Author: michaelklishin

docs/rabbitmq-diagnostics.8

@@ -102,10 +102,12 @@ To learn more, see the
 .\" ------------------------------------------------------------------
 .Sh COMMANDS
 .\" ------------------------------------
-.Ss Topology Introspection
 .Pp
-The topology introspection commands list topology entities (e.g. queues) with tab-delimited columns.
-.
+Most commands provided by
+.Nm
+inspect node and cluster state or perform health checks.
+.Pp
+Commands that list topology entities (e.g. queues) use tab as column delimiter.
 These commands and their arguments are delegated to rabbitmqctl(8).
 .Pp
 Some commands (