ci: Run rustfmt on changed files

.ci/check-style

@@ -9,6 +9,7 @@ set -e
 set -o pipefail
 
 CLANGFORMAT=${CLANGFORMAT:-clang-format-18}
+RUSTFMT=${RUSTFMT:-rustfmt}
 
 command -v git >/dev/null 2>&1 || { echo >&2 "git is missing"; exit 1; }
 command -v xargs >/dev/null 2>&1 || { echo >&2 "xargs is missing"; exit 1; }
@@ -37,3 +38,9 @@ if git --no-pager diff --diff-filter=d --name-only ${TARGET_BRANCH} HEAD | grep
 	git --no-pager diff
 	exit 1
 fi
+
+RUST_SOURCES=$(git --no-pager diff --diff-filter=d --name-only ${TARGET_BRANCH} HEAD | grep -E "^src/rust.*\.rs\$" | grep -v -E "^src/rust/vendor" || true)
+if [ -n "$RUST_SOURCES" ] ; then
+        echo $RUST_SOURCES
+	"$RUSTFMT" --check $RUST_SOURCES
+fi

.ci/ci

@@ -6,7 +6,7 @@ set -e
 # Deny warnings in rust. CI will fail to compile any code with warnings in it.
 export RUSTFLAGS="-Dwarnings"
 
-# Check style for C
+# Check style for C and Rust
 ./.ci/check-style
 
 # Check that we can generate protobuf definitions for python