Add llvm tools

.tangled/workflows/test.yml

···
 dependencies:
   nixpkgs:
     - rustup
-    - clang
 
 steps:
   - name: Install Nightly
     command: rustup toolchain install nightly
   - name: Install toolchain
     command: rustup +nightly target install thumbv7em-none-eabihf
+  - name: LLVM tools
+    command: rustup component add llvm-tools 
   - name: Install flip-link
     command: cargo install --locked flip-link
   - name: Format Check