rename or refname

[braingram]

As found in #80

sphinx-asdf/sphinx_asdf/directives.py

Lines 210 to 217 in 97f22f6

	elif shorten:
	# TODO this should probably be:
	# refname = schema_id
	# as it was previously
	# rename = schema_id
	# and ruff cleaned this up as unused. However, changing it
	# to refname breaks some downstream packages
	pass

Determine if this should be refname and why it breaks downstream packages.