Fixes: #18568 Update mkdocstrings and adapt config (#18841)

* Fixes: #18568 Update mkdocstrings and adapt config

* Fixed some output formatting errors

When trying to compare the output from "mkdocstrings[python-legacy]==0.27.0" and
"mkdocstrings[python]==0.28.2" I encountered some HTML errors:
- <div> inside a <p>
- unescaped non-tags <pk>

docs/administration/authentication/overview.md

@@ -54,6 +54,7 @@ Icons](https://github.com/google/material-design-icons) icon's name; or be
 `None` for no icon.
 
 For instance, the OIDC backend may be customized with
+
 ```python
 SOCIAL_AUTH_BACKEND_ATTRS = {
     'oidc': ("My awesome SSO", "login"),