Add chemistry shack PoI to Shaded Hills

[out-of-phaze]

Description of changes

adds a chemistry shack PoI to Shaded Hills, by @noelle-lavenza also fixes an issue i spotted with the fox/bear den submaps

needs #4338

Why and what will this PR improve

fixes bear den adds a new map at Loaf's behest, for Variety

Authorship

map and associated code is by Noelle, fix is by me

Changelog

:cl: add: Added a chemistry shack to the list of Shaded Hills woodland points of interest. bugfix: Fixed spawning bear dens in the woods on Shaded Hills. /:cl: