OSDOCS-5334 Adding namespace option to oc adm must-gather

Author: cbippley

modules/about-must-gather.adoc

@@ -57,3 +57,11 @@ openshift-must-gather-5drcj    must-gather-s8sdh    2/2     Running     0
 ...
 ----
 // todo: table or ref module listing available images?
+Optionally, you can run the `oc adm must-gather` command in a specific namespace by using the `--run-namespace` option.
+
+For example:
+
+[source,terminal,subs="attributes+"]
+----
+$ oc adm must-gather --run-namespace <namespace> --image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel8:v{product-version}.0
+----