Describe the bug
#7061 contained a workaround to unbreak the bug where :attr: wasn’t able to refer to properties.

unfortunately the workaround doesn’t address intersphinx links, as intersphinx relies on the missing-reference hook to resolve references. The resolve_xref function containing the workaround always returns None for intersphinx links, and intersphinx’ missing-reference hook doesn’t contain a workaround.

#7068 is the correct fix for this problem that makes further workarounds unnecessary.

To Reproduce

echo >conf.py <<EOF
extensions = ["sphinx.ext.intersphinx"]
intersphinx_mapping = dict(pandas=("https://pandas.pydata.org/pandas-docs/stable/", None))
EOF
echo ':attr:`pandas.DataFrame.iloc`' >index.rst
sphinx build . html

Expected behavior

• :attr: links to properties work with intersphinx as well (fixed by Document properties as attributes #7068, could also be fixed by another workaround)
• objects.inv contains entries for properties under py:attribute (fixed by Document properties as attributes #7068)

Environment info

• OS: All
• Python version: 3.8
• Sphinx version: 2.4.1
• Sphinx extensions: sphinx.ext.intersphinx