Bump basic_materials from `9d55f99` to `b9ac857`

Bumps [basic_materials](https://github.com/mt-mods/basic_materials) from `9d55f99` to `b9ac857`.
- [Release notes](https://github.com/mt-mods/basic_materials/releases)
- [Commits](https://github.com/mt-mods/basic_materials/compare/9d55f9916d20779ecbf93c7e95dae8adebd2079b...b9ac85790df6416085870d8acbb7eb4a3f5d4040)

basic_materials @ b9ac8579

-Subproject commit 9d55f9916d20779ecbf93c7e95dae8adebd2079b
+Subproject commit b9ac85790df6416085870d8acbb7eb4a3f5d4040