Replace Sphinx napoleon for numpydoc (#84)

Replace the builtin Sphinx plugin `napoleon` for generating the
summaries of functions and classes for the `numpydoc` plugin. Include
`numpydoc` as a requirement for building the docs and in
`environment.yml`. Configure Sphinx to use `numpydoc` when building the
docs.

doc/conf.py

@@ -22,13 +22,13 @@
 extensions = [
     "sphinx.ext.autodoc",
     "sphinx.ext.autosummary",
+    "numpydoc",
     "sphinx.ext.coverage",
     "sphinx.ext.mathjax",
     "sphinx.ext.doctest",
     "sphinx.ext.viewcode",
     "sphinx.ext.extlinks",
     "sphinx.ext.intersphinx",
-    "sphinx.ext.napoleon",
     "sphinx_design",
     "sphinx_copybutton",
     "jupyter_sphinx",
@@ -45,11 +45,12 @@
 # Autosummary pages will be generated by sphinx-autogen instead of sphinx-build
 autosummary_generate = []
 
-# Otherwise, the Return parameter list looks different from the Parameters list
-napoleon_use_rtype = False
-# Otherwise, the Attributes parameter list looks different from the Parameters
-# list
-napoleon_use_ivar = True
+# Create cross-references for the parameter types in the Parameters, Other
+# Returns and Yields sections of the docstring
+numpydoc_xref_param_type = True
+
+# Format the Attributes section like the Parameters section.
+numpydoc_attributes_as_param_list = True
 
 # Sphinx project configuration
 templates_path = ["_templates"]

env/requirements-docs.txt

@@ -1,5 +1,6 @@
 # Requirements for building the documentation
 sphinx==7.2.*
+numpydoc==1.7.*
 sphinx-book-theme==1.1.*
 sphinx-copybutton==0.5.*
 sphinx-design==0.5.*

environment.yml

@@ -17,6 +17,7 @@ dependencies:
   - coverage
   # Documentation
   - sphinx==7.2.*
+  - numpydoc==1.7.*
   - sphinx-book-theme==1.1.*
   - sphinx-copybutton==0.5.*
   - sphinx-design==0.5.*