Add support for terrain 'globs' (dubbed 'beardification' by mojang) to generate under injected structures that are listed under StructureFeature.NOISE_AFFECTING_FEATURES (mojmap).

Fabric 1.17.1 Terra 5.4.1 with vanilla.structures enabled

Terrain 'Globs' under a village house from beardification (provided by @TelepathicGrunt)

For an implementation that uses the same technique as vanilla, we would have to split fetching noise from the Sampler, and palette application into two distinct stages within the generator, then sandwich injected structure generation between them, in order for the terrain to blend. This could lend itself to working with #92 too.

For a more approximate approach we could make the terrain globs independent of noise, which would allow structure population to be placed in the population order arbitrarily.

implemented in 069b0d4