Cahnge Helm installer "singleNamespace" convention

This comments out and describes what this attribute does, which
is effectively a no-op but moves this closer to Helm conventions.

helm/install/values.yaml

@@ -19,8 +19,11 @@ relatedImages:
   pgexporter:
     image: registry.developers.crunchydata.com/crunchydata/crunchy-postgres-exporter:ubi8-5.0.4-0
 
-## Install in default or single namespace mode
-singleNamespace: false
+# singleNamespace determines how to install PGO to watch namesapces. If set to
+# false, PGO will watch for Postgres clusters in all namesapces Setting to
+# "true" will instruct PGO to only watch for Postgres clusters in the namespace
+# that it is installed in.
+# singleNamespace: false
 
 # debug allows you to enable or disable the "debug" level of logging.
 # Defaults to the value below.