docs(api) Visual improvements via gp-sphinx (#658)

Adopt the gp-sphinx Sphinx package stack for libtmux's API
documentation. The net visual effect is card-style autodoc
signatures with safety and scope badges, MyST cross-reference
roles for Python objects, scoped section names in multi-page CLI
docs, and polished IBM Plex typography — all landing together from
the gp-sphinx 0.0.1a7 pre-release.

- **API-style autodoc layout** via sphinx-autodoc-api-style —
  card layouts, badges, MyST roles for Python objects
- **Shared badge layer** via sphinx-autodoc-badges — consistent
  XS/SM/LG/XL size variants with WCAG-AA contrast
- **Multi-page argparse scoping** via sphinx-argparse-neo — CLI
  doc builds no longer emit duplicate-label warnings
  (git-pull/gp-sphinx#16)
- **Font polish** via sphinx-fonts — IBM Plex Sans and Mono at
  full weight range, zero-CLS loading

See gp-sphinx 0.0.1a7 release notes for the full list of changes
covering 0.0.1a1..0.0.1a7:
https://github.com/git-pull/gp-sphinx/blob/v0.0.1a7/CHANGES

Author: tony

CHANGES

@@ -40,6 +40,11 @@ $ uvx --from 'libtmux' --prerelease allow python
 _Notes on the upcoming release will go here._
 <!-- END PLACEHOLDER - ADD NEW CHANGELOG ENTRIES BELOW THIS LINE -->
 
+### Documentation
+
+- Visual improvements to API docs from [gp-sphinx](https://gp-sphinx.git-pull.com)-based Sphinx packages (#658)
+
+
 ### What's new
 
 #### pytest plugin: fixture reference documentation with autofixture directives (#656)

docs/conf.py

@@ -30,7 +30,11 @@
     source_branch="master",
     light_logo="img/libtmux.svg",
     dark_logo="img/libtmux.svg",
-    extra_extensions=["sphinx_autodoc_pytest_fixtures", "sphinx.ext.todo"],
+    extra_extensions=[
+        "sphinx_autodoc_api_style",
+        "sphinx_autodoc_pytest_fixtures",
+        "sphinx.ext.todo",
+    ],
     intersphinx_mapping={
         "python": ("https://docs.python.org/", None),
         "pytest": ("https://docs.pytest.org/en/stable/", None),

pyproject.toml

@@ -52,8 +52,9 @@ Changes = "https://github.com/tmux-python/libtmux/blob/master/CHANGES"
 [dependency-groups]
 dev = [
   # Docs (via gp-sphinx)
-  "gp-sphinx==0.0.1a1",
-  "sphinx-autodoc-pytest-fixtures==0.0.1a1",
+  "gp-sphinx==0.0.1a7",
+  "sphinx-autodoc-api-style==0.0.1a7",
+  "sphinx-autodoc-pytest-fixtures==0.0.1a7",
   "sphinx-autobuild",
   "types-docutils",
   # Testing
@@ -74,8 +75,9 @@ dev = [
 ]
 
 docs = [
-  "gp-sphinx==0.0.1a1",
-  "sphinx-autodoc-pytest-fixtures==0.0.1a1",
+  "gp-sphinx==0.0.1a7",
+  "sphinx-autodoc-api-style==0.0.1a7",
+  "sphinx-autodoc-pytest-fixtures==0.0.1a7",
   "sphinx-autobuild",
 ]
 testing = [