Fix fmt

.devcontainer/Dockerfile

@@ -19,7 +19,8 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 
 RUN groupadd --gid ${USER_GID:-1000} $USERNAME \
     && useradd --uid ${USER_UID:-1000} --gid ${USER_GID:-1000} -m $USERNAME \
-    && rustup component add clippy
+    && rustup component add clippy \
+    && rustup component add rustfmt