Non-functions in the `See Also` section

[crusaderky]

The See Also section should be explicitly allowed to contain references to any object.

The current situation is murky:

• The documentation exclusively mentions functions, without explicitly ruling out other entities.
  https://numpydoc.readthedocs.io/en/latest/format.html#see-also
• numpydoc parses untagged entries in the section to match anything
• numpydoc.docscrape automatically adds the :func: tag to untagged entries, but otherwise accepts other entries.

This causes problems for example with numpy/numpy#28734.
This works with intersphinx:

def f():
    """
    See Also
    --------
    numpy.logaddexp
    """

However, a round-trip through docscrape breaks it:

def f():
    """
    See Also
    --------
    numpy.logaddexp
    """

from numpydoc.docscrape import FunctionDoc
f.__doc__ = str(FunctionDoc(f))

Now f.__doc__ has been changed to

.. function:: f
    




See Also
--------

:func:`numpy.logaddexp`
    ..

Which encroaches on numpy/numpy#28734 and breaks the rendering, because numpy.logaddexp is actually a py:data object.