mark display_psf_grid as deprecated

[mperrin]

This addresses #887 by marking display_psf_grid as deprecated, using an astropy decorator for marking deprecation.

I'm not actually sure this is the best way to do this, and welcome suggestions if there's a better way. I see there's also a PEP 702 to add a similar @deprecated to the standard library but it's not yet available even in py 3.12, so that doesn't work. In any case we can informally deprecate (and I'm separately revising the docs and example code in #899 already), so this PR is just attempting to mark the deprecation in code, in some suitable manner.

[pep8speaks]

Hello @mperrin, Thank you for updating !

There are no PEP8 issues in this Pull Request.

Comment last updated at 2024-08-05 17:57:23 UTC

[BradleySappington]

@mperrin - this is a working solution, however the warning looks like an astropy method is what is being deprecated. This may be confusing to the user (or it may not?)

I don't think we should included a deprecated library install for something like this, so we can either keep as you proposed, or just construct our own warning as so:

import warnings

warnings.simplefilter('always', DeprecationWarning)

def display_psf_grid((grid, zoom_in=True, figsize=(14, 12), scale_range=1e-4, diff_scale_range=1, cmap=None):

warnings.warn( "The display_psf_grid function is deprecated and may be removed in a future version." "Use photutils.psf.GriddedPSFModel.plot_grid instead.", DeprecationWarning, stacklevel=2 )