added option `google-readability-namespace-comments.AllowNoNamespaceComments` (#124265)
New option AllowNoNamespaceComments for
`google-readability-namespace-comments.AllowNoNamespaceComments` is
added.
When true, the check will allow that no namespace comment is present. If
a namespace comment is added but it is not matching, the check will
fail. Default is `false`
Fixes #124264