add comment for samples owner

Author: parthea

synthtool/gcp/templates/python_library/.github/CODEOWNERS

@@ -8,10 +8,12 @@
 # @googleapis/yoshi-python and {{ metadata['repo']['codeowner_team'] }} are the default owners for changes in this repo
 *     @googleapis/yoshi-python {{ metadata['repo']['codeowner_team'] }}
 
+# @googleapis/python-samples-owners and {{ metadata['repo']['codeowner_team'] }} are the default owners for samples changes
 /samples/   @googleapis/python-samples-owners {{ metadata['repo']['codeowner_team'] }}
 {% else %}
 # @googleapis/yoshi-python is the default owner for changes in this repo
 *     @googleapis/yoshi-python
 
+# @googleapis/python-samples-owners is the default owner for samples changes
 /samples/   @googleapis/python-samples-owners
 {% endif -%}