switch documentation to furo theme

Because cleaner look, more useful contents sidebar and light/dark mode support.

docs/conf.py

@@ -48,9 +48,7 @@ exclude_patterns = ['_build', 'Thumbs.db', '.DS_Store']
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-import sphinx_theme_pd
-html_theme = 'sphinx_theme_pd'
-html_theme_path = [sphinx_theme_pd.get_html_theme_path()]
+html_theme = 'furo'
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,

docs/requirements.txt

@@ -1,4 +1,4 @@
 reno[sphinx]==3.5.0
 Sphinx==5.1.1
-sphinx-theme-pd==0.8.3
+furo==0.8.3