Add note about property metrics (#18678)

* Add note about property metrics

* Apply suggestions from code review

Co-authored-by: DeForest Richards <56796055+drichards-87@users.noreply.github.com>

---------

Co-authored-by: DeForest Richards <56796055+drichards-87@users.noreply.github.com>

vsphere/README.md

@@ -57,6 +57,18 @@ collect_per_instance_filters:
 
 `disk` metrics are specific for each disk on the host, therefore these metrics need to be enabled using `collect_per_instance_filters` to be collected.
 
+#### Collecting property metrics
+
+The vSphere integration can also collect property-based metrics. These are configuration properties, such as if a host is in maintenance mode or a cluster is configured with DRS.
+
+To enable property metrics, configure the following option:
+```
+collect_property_metrics: true
+```
+
+Property metrics are prefixed by the resource name. For example, host property metrics metrics are prefixed with `vsphere.host.*`, and VM property metrics are prefixed with `vsphere.vm.*`. View all the possible property metrics in the [metadata.csv][10].
+
+
 ### Events
 
 This check watches vCenter's Event Manager for events and emits them to Datadog. The check defaults to emit the following event types: