While `static` compiles, it causes issues with VSCode's rust-analyzer extension the below error. Normally `static` is used for objects that require a heap allocation. `const` is the idiomatic (and equivalent) way of defining a plain-old-data (POD) type like an integer.

```
thread 'Worker7' (220875) panicked at crates/hir-ty/src/next_solver/interner.rs:1133:18:
not implemented: Unexpected alias: StaticId("FREEFLOW_BUFFER_SIZE")
stack backtrace:
```

Note that this is not a functional issue with our code, but a change to more idiomatic usage that works around an issue in the rust-analyzer extension.