When rendering docs, preserve the syntax for defaults. Fixes jaraco/p…

…ath#197.

Incidentally, re-organize the extensions a bit for clarity.

docs/conf.py

@@ -1,10 +1,15 @@
 #!/usr/bin/env python3
 # -*- coding: utf-8 -*-
 
-extensions = ['sphinx.ext.autodoc', 'jaraco.packaging.sphinx', 'rst.linker']
+extensions = [
+    'sphinx.ext.autodoc',
+    'jaraco.packaging.sphinx',
+]
 
 master_doc = "index"
 
+# Link dates and other references in the changelog
+extensions += ['rst.linker']
 link_files = {
     '../CHANGES.rst': dict(
         using=dict(GH='https://github.com'),
@@ -25,7 +30,7 @@
     )
 }
 
-# Be strict about any broken references:
+# Be strict about any broken references
 nitpicky = True
 
 # Include Python intersphinx mapping to prevent failures
@@ -34,3 +39,6 @@
 intersphinx_mapping = {
     'python': ('https://docs.python.org/3', None),
 }
+
+# Preserve authored syntax for defaults
+autodoc_preserve_defaults = True

setup.cfg

@@ -46,7 +46,7 @@ testing =
 
 docs =
 	# upstream
-	sphinx
+	sphinx >= 3.5
 	jaraco.packaging >= 9
 	rst.linker >= 1.9