docs: Update intersphinx location for py3k and automate maintenance

seed_intersphinx_mapping will read pyproject collecting the list of
deps and trying to load intersphinx objects from it.  This should
remove the need for us to manage this by hand.

That change will pull in lazy_objects sphinx docs whenever they
write said sphinx docs.

Signed-off-by: Brian Harring <[email protected]>

doc/conf.py

@@ -51,6 +51,7 @@
     "sphinx.ext.ifconfig",
     "sphinx.ext.graphviz",
     "sphinx.ext.viewcode",
+    "seed_intersphinx_mapping",
 ]
 
 # Add any paths that contain templates here, relative to this directory.
@@ -241,7 +242,13 @@
 
 
 # Example configuration for intersphinx: refer to the Python standard library.
-intersphinx_mapping = {"http://docs.python.org/": None}
+intersphinx_mapping = {
+    "python": ("https://docs.python.org/3", None),
+}
+
+# directive to seed_intersphinx_mapping; we use pyproject, thus read that.
+pkg_requirements_source = "pyproject"
+
 autodoc_default_flags = [
     "members",
     "show-inheritance",

pyproject.toml

@@ -34,7 +34,10 @@ test = [
     "pytest >=6.0",
     "pytest-cov",
 ]
-doc = ["sphinx"]
+doc = [
+	"sphinx",
+	"seed_intersphinx_mapping"
+]
 
 [project.urls]
 Homepage = "https://github.com/pkgcore/snakeoil"