Docs builds failing

[jaraco]

The docs are failing with this warning:

WARNING: error while formatting arguments for irc.client.PrioritizedHandler: Handler <function update_defvalue at 0x105389a80> for event 'autodoc-before-process-signature' threw an exception (exception: )

There's nothing particularly special about that class:

irc/irc/client.py

Lines 682 to 685 in 6a3c948

	class PrioritizedHandler(collections.namedtuple('Base', ('priority', 'callback'))):
	def __lt__(self, other):
	"when sorting prioritized handlers, only use the priority"
	return self.priority < other.priority

[jaraco]

Upstream issue is sphinx-doc/sphinx#11543.