Autonote symbol for derelict shed

[Valares]

Summary

None

Purpose of change

The autonote function does not create autonotes for collapsed sheds, although they might be interesting enough for a survivor to take note of. It might also create confusion to find a building in a random place with no corresponding symbol on the map.
Furthermore, the autonote does mark burned ground with a yellow colored point, which isn't really representitive of the remaining ash.

Describe the solution

Added an autonote symbol for the derelict shed map extra: A dark gray ^.
Also changed the color of the burned map tiles to light gray to better represent the ash.

Describe alternatives you've considered

The color gray is a bit tricky to see, and I'm not sure how well it works for people with color vision deficiency, so I've considered other colors instead, but there were none that would really fit. Dark gray is even worse for the burned ground/point, and brown for the shed made it look weird in my opinion.

Testing

Created a new world and verified that the symbol did show up and were the right color.

Additional context

Screenshots of a shed and right below it a burned tile:

[pjf]

The color gray is a bit tricky to see, and I'm not sure how well it works for people with color vision deficiency.

Deuteranomaliac here, reporting in that the tile has plenty of contrast for me, because it has extra brightness compared to the surrounding fields.

[Valares]

Deuteranomaliac here, reporting in that the tile has plenty of contrast for me [...]

Thank you for reporting in, that's really good to know.