Congressional districts update about algorithms

[depryf]

@howew can you please submit an issue in the Call for Data squish project for this work? The one that is opened for Congressional Districts is set to 2025 submission; I don't see one for 2024.

I have questions about this and I think they should be handled in that Squish project.

[depryf]

The Congressional District data is contained in the SEER data posted on the SEER website, but we are not currently using it (we use a standalone CSV to load that data).

I believe we want to switch to the SEER data, but it it's a 4-characters code instead of a 2-digits code (it contains the state as a prefix). We are trying to determine if it's OK to switch to the 4-characters code in this library, or if we want to stick with the 2 digits...

[depryf]

I switched to the SEER data and I am removing the state prefix so the output is the same as before.

If we want to include the state, it's a very simple change. We will need another issue for that.