Add weeds to standard_domestic_landscaping_palette

[Milopetilo]

Summary

None

Purpose of change

I discovered there's weeds in the game, I'd assume most places would at least have a few around.

Describe the solution

Adds weeds to standard_domestic_landscaping_palette so they spawn instead of flowers sometimes.

Describe alternatives you've considered

I wanted to add the weeds to standard_domestic_palette to have them spawn on any t_region_groundcover_urban but I ran into the problem that sometimes . is used on a second story as t_open_air and it'd be a lot of trouble to fix and make sure no-one else in the future runs into the issue. As a result I have added weeds to . in standard_domestic_landscaping_palette since that is usually only used on ground floors, but that also failed :/

Testing

Game loads, weeds spawn, noticed no errors thrown.

Additional context