Add `fill_biome` function to the environment module

[aksiome]

🗂️ Request Type

Feature

🧩 Feature or Module Name

#bs.environment:fill_biome

📝 Description

Introduce a fill_biome function to the environment module that allows filling a specified area with a given biome.

[aure31]

what's the difference between the function and the vanilla fillbiome command?

[aksiome]

Someone suggested adding a special mask or filter for this, similar to what we have in the block module. That could definitely be useful in the future, but I think even a simpler version would already be helpful. It would save users from having to write their own macro function for something the library can handle directly.