Grammar.

Author: Marcelo Vanzin

docs/monitoring.md

@@ -1160,7 +1160,7 @@ easily add other plugins from the command line without overwriting the config fi
 plugins are ignored.
 
 Distribution of the jar files containing the plugin code is currently not done by Spark. The user
-or admin should make sure that the jar file is available to Spark applications, for example, by
+or admin should make sure that the jar files are available to Spark applications, for example, by
 including the plugin jar with the Spark distribution. The exception to this rule is the YARN
 backend, where the <code>--jars</code> command line option (or equivalent config entry) can be
 used to make the plugin code available to both executors and cluster-mode drivers.