docs: Generate "Deprecated" admonitions automatically

Wire the `griffe-warnings-deprecated` extension into the mkdocstrings
handler options, so every symbol decorated with
`typing_extensions.deprecated` gets a "Deprecated" admonition in the
API reference with no docstring edit at all.

The extension's `kind` is set to `deprecated` rather than the default
`warning`, so it emits `class="deprecated"`, which is exactly what
a hand-written `Deprecated:` admonition produces. The CSS rule added
in the previous commit then styles both, and the two are visually
indistinguishable. That matters because the decorator cannot reach
everything: module-level aliases, a single function argument, enum
members and whole modules still need the admonition written by hand.

Signed-off-by: Leandro Lucarella <luca-frequenz@llucax.com>

Author: llucax

mkdocs.yml

@@ -101,6 +101,10 @@ plugins:
         python:
           paths: ["src"]
           options:
+            extensions:
+            - griffe_warnings_deprecated:
+                kind: deprecated
+                title: Deprecated
             docstring_section_style: spacy
             inherited_members: true
             merge_init_into_class: false

pyproject.toml

@@ -55,6 +55,7 @@ dev-flake8 = [
 dev-formatting = ["black == 26.5.1", "isort == 8.0.1"]
 dev-mkdocs = [
   "black == 26.5.1",
+  "griffe-warnings-deprecated == 1.1.1",
   "Markdown==3.10.3",
   "mike == 2.2.0",
   "mkdocs-gen-files == 0.6.1",