radec_to_desiname should include bounds checks

[weaverba137]

As mentioned in desihub/desispec#2238, NaN can result in obviously bad values of DESINAME:

>>> import numpy as np
>>> from desiutil.names import radec_to_desiname
>>> radec_to_desiname(np.nan, np.nan)
array(['DESI J-922337203685477.5808-922337203685477.5808'], dtype='<U48')

Other bounds should also be checked:

• NaN
• Inf
• RA not in [0, 360).
• Dec not in [-90, 90].

The proposal is that any value that exceeds these bounds should trigger an exception. We can issue exception messages that are easy to understand, e.g., "Dec values outside of the range [-90, 90] detected." but it should still raise the exception rather than "soldiering on".

@sbailey, @akremin, @schlafly any opinions on the exception, or other bounds that should be checked?

[akremin]

I think a ValueError for the 4 checks you mentioned would make a lot of sense.

[sbailey]

Sounds good, and +1 for including an informative exception message. I'd suggest also including the invalid value itself in the message and not just that an invalid value was detected and what the good range is.

[weaverba137]

@sbailey I thought about that, but it could be inconvenient if the inputs are large arrays. Inf or NaN is easy, I'm thinking more about out-of-bounds RA, Dec.