Outdated NSRDB PSM3 documentation link returns 404 Not Found

[ayushjariyal]

Describe the bug
The documentation link for PSM3 Data Download in the pvlib code and references is outdated and returns a 404 Not Found error.

To Reproduce
Steps to reproduce the behavior:

1. Go to the following NSRDB API documentation link:
   https://developer.nrel.gov/docs/solar/nsrdb/psm3_data_download/
2. The page returns 404 Not Found.

Expected behavior
The link should point to the correct documentation page for PSM3 Data Download in the NSRDB API.

Additional context

1. The API endpoints seem to be working, but the documentation link is no longer valid.
2. The latest documentation link should be updated in the pvlib codebase and references.
3. Possible alternative documentation: https://developer.nrel.gov/docs/solar/nsrdb/

[RDaxini]

Could you link the docs page where you found this broken link?
References on iotools.get_psm3 seem to be working fine. I noticed the link in the changed in version 10.0 warning on that page does not work, but that's different to the link you have shared.

[williamhobbs]

There's an issue with the link here:

pvlib-python/pvlib/iotools/psm3.py

Lines 1 to 4 in 2ca40aa

	"""
	Get PSM3 TMY
	see https://developer.nrel.gov/docs/solar/nsrdb/psm3_data_download/
	"""

There's also the confusing note Get PSM3 TMY, which relates to the point @kandersolar brought up here #2326 (comment) about having different API endpoints (TMY, etc.) in the same function.

It should probably list out the different documentation links if the psm3 tools are going to stay in a single function, e.g.,

"""
Get PSM3 data from several endpoints. See:
https://developer.nrel.gov/docs/solar/nsrdb/psm3-2-2-tmy-download/
https://developer.nrel.gov/docs/solar/nsrdb/psm3-2-2-download/
https://developer.nrel.gov/docs/solar/nsrdb/psm3-5min-download/
"""

[kandersolar]

git grep is a handy tool for finding things like this. It shows that @williamhobbs found the only location of that particular url:

$ git grep -n psm3_data_download
pvlib/iotools/psm3.py:3:see https://developer.nrel.gov/docs/solar/nsrdb/psm3_data_download/

[echedey-ls]

I'm unable to find a documentation index in ReadTheDocs for pvlib.iotools.psm3, which is where I would expect that link to be. This must be what @RDaxini was referring to, and makes for another issue.
We could ensure API links work by hyperlinking them, for the links check step in the release procedure to analyse them. But for that to work, they have to be included in public docs.