Instead of having to override everything that "contains
cobble", which keeps expanding/evolving, some simple
compromises to the gravel texture (darkening, and a
few extra dark spots) allows the see-thru cobble
texture to reach very close to the desired look for all
compound cobble-over-gravel uses, making this
texturepack require far fewer overrides.
- Allow cobble-containing nodes to show the inner substance through
the cracks between stones.
- Fix grass side texture, broken with 2020-02-18 upstream texturing
changes.
