refactor: move firmware workspace under firmware

docs/src/reference.md

@@ -20,6 +20,7 @@ upload sequence, [Logs](logs.md) for receiver decoding and filtering, and
 Before review, run:
 
 ```sh
+cd firmware
 cargo fmt --all --check
 cargo test --workspace --locked --offline
 cargo clippy --workspace --all-targets --locked -- -D warnings