Updating evolution locations

[jemarq04]

This is a follow-up on PR #1525 and our discussion to swap the location_id field in pokemon_evolution.csv with location_area_id, to hopefully be more descriptive on the locations for the evolution.

Unfortunately, digging into this further has shown it's not that simple. If we're doing this to be more descriptive with the "rock" evolutions (e.g. Leafeon with the Mossy Rock), it'll essentially be the same issue as before since we can't accurately describe the condition as "near the rock". Additionally, some evolutions are dependent on the entire location (e.g. Magneton can evolve in any location area within Mt. Coronet). Making an evolution entry for each of these location areas seems excessive.

I propose a few options for how to proceed:

1. We leave the evolution condition as-is with the location specified. This would only negatively impact the older evolutions requiring the special rocks (Leafeon/Glaceon).
2. Leaving the evolutions as-is but we add an additional evolution field such as near_special_rock, which would be a boolean set to true only for the relevant evolutions. This would only be needed for Leafeon and Glaceon, as the other location-based evolutions cover the entire location.
3. Make the switch to location area IDs, but create a new "virtual" location area ID that would contain no encounters but would be tied to the evolution for clarity. For example, creating a eterna-forest-near-mossy-rock location area purely for the evolution condition. Similarly, we'd need to create a base mt-coronet location area (though a 'default' one of course does not exist in-game) which would be pointed to for the relevant evolutions.

Any of these options would be reasonable, but each have their drawbacks. I'm torn between option 2 and 3, but I'd like to get some input from others to see what we'd think as far as upkeep and clarity before I make any changes. (I'll ping @notblisy @Naramsim @FreakMediaLP as well.)

[Naramsim]

I'd go with 1 honestly. Leaving as it is now. There are so many fine details about how-you-can-do-sometihing in the pokemon games, and we lack all the granularity needed for thoroughly documenting those.

Go with 2 or 3 if you have time to spare

[jemarq04]

I’ve got both options ready for a PR depending on what we think is best. I’m leaning towards option 2, but the original idea was for location areas so I wanted to express thoughts on that in case others had opinions.

If you think these are fine, I’ll just make a PR with option 2