show_if_no_docstring does not collect objects with no docstring in new Python handler

[johnthagen]

Describe the bug

Enabling show_if_no_docstring in the new Python handler (#364) setting does not collect packages or modules without a docstring.

  - mkdocstrings:
      handlers:
        python:
          selection:
            show_if_no_docstring: true

To Reproduce

A full reproducible project is here:

• Update to new mkdocstrings Python handler johnthagen/python-blueprint#82

Steps to reproduce the behavior:

1. In that PR, install tox and run tox -e docs-serve
2. Navigate to the API page:

Expected behavior
As with the legacy Python handler, there would be a way to collect all files in a package, regardless of if some of the items in the tree have a docstring.

Information (please complete the following information):

• OS: MacOS
• Browser: Chrome
• mkdocstrings version: 0.18.0

Full requirements: https://github.com/johnthagen/python-blueprint/pull/82/files#diff-43470c4f399e798afc682f0bf6c690eef5f47ee25445904a066e4c3314f3a787

Additional Context

Full mkdocs.yml:

# Set strict to true to turn warnings into errors to catch warnings within CI.
strict: true
theme:
  name: material
  # By default, fonts are pulled from Google on the Internet. To support offline usage, this is
  # disabled.
  font: false
  palette:
    scheme: slate
    primary: green
    accent: yellow
  icon:
    logo: material/math-integral-box
    # GitHub specific.
    repo: fontawesome/brands/github
  favicon: static/math-integral-box.png
  features:
    - content.code.annotate
    - navigation.tracking
    - search.highlight
    - search.share
    - search.suggest
markdown_extensions:
  - admonition
  - pymdownx.keys
  - pymdownx.highlight
  - pymdownx.superfences
  - pymdownx.snippets
  - pymdownx.tabbed:
      alternate_style: true
extra:
  social:
    - icon: fontawesome/brands/github
      link: https://github.com/johnthagen/python-blueprint
# This is needed to allow links to work when opened from the file system.
use_directory_urls: false
plugins:
  - search
  - mkdocstrings:
      handlers:
        python:
          selection:
            show_if_no_docstring: true
      watch:
          - src
  # This plugin is used to validate URLs (including some anchors).
  # Uncomment to build the docs with this validation enabled.
  # This is commented out by default because this requires network I/O to validate URLs, so it is
  # inherently not exactly reproducible. But this plugin is none-the-less helpful at detecting
  # incorrect URLs.
#  - htmlproofer:
#      raise_error: True
site_name: fact
copyright: Copyright © 2018-2021 John Hagen
# GitHub Specific Configuration.
repo_name: python-blueprint
repo_url: https://github.com/johnthagen/python-blueprint
edit_uri: edit/master/docs/user_guide/docs/

[johnthagen]

A version that is built with the legacy handler is currently hosted here: https://johnthagen.github.io/python-blueprint/api.html

[pawamoy]

Try to put show_if_no_docstring under rendering instead of selection 😉

[johnthagen]

🤦 I see now that the examples are below the definition. This makes sense now that I know. As a new user reading the docs, the selection example is so close to the top of Rendering I didn't realize that Rendering had it's own examples further down.

Not sure there is anything actionable, but at least you got some feedback from a first time user.

Thanks for the great package!