Small rewording about history server use case

Hello
PR #10991 removed the built-in history view from Spark Standalone, so the history server is no longer useful to Yarn or Mesos only.

Author: Hervé <[email protected]>

Closes #17709 from dud225/patch-1.

Author: dud225

docs/monitoring.md

@@ -27,8 +27,8 @@ in the UI to persisted storage.
 
 ## Viewing After the Fact
 
-If Spark is run on Mesos or YARN, it is still possible to construct the UI of an
-application through Spark's history server, provided that the application's event logs exist.
+It is still possible to construct the UI of an application through Spark's history server, 
+provided that the application's event logs exist.
 You can start the history server by executing:
 
     ./sbin/start-history-server.sh