Purpose of change

Another lil innawoods balance adjustment while I'm failing at going to bed. Aim is to sanity-check the frequency of bog iron, cacao trees, and coca plants.

Describe the solution

1. Doubled the weights used in t_region_groundcover_swamp while keeping bog iron at its original weight, with the aim of making it half as common as before.
2. Reduced weights of cacao and coca trees in t_region_tree to 1 instead of 2.
3. Reduced weight of cacao trees in t_region_tree_shade to 1 and removed coca plants from it, as that wouldn't exactly count as a shade tree.
4. Reduced weight of cacao tree in t_region_tree_fruit to 1 since the total weights here are also vastly lower.
5. Updated description of coca plant to allude to the likely medical research origin of it being modified to show up here, with the implication that it's wild appearance is accidental. Also removed reference to it being a tree you can chop down since it lacks that flag.
6. Also fixed the harvested coca plant still having the same name as the ready-to-pick variant.
7. Updated the regional map settings override in rural biome mod accordingly.

Describe alternatives you've considered

Adding a botanical research institute in the future that serves as a fitting place to find plenty of the more out-there plant types. Probably with a decent chance of being infested with triffids, and maybe with a fungal-infested variant (separate so no Fungal Monsters can blacklist it properly).

Testing

Checked affected files for syntax and lint errors.

Additional context

Checklist