Add a rustfmt syntactic check for the Rust project

Author: NlightNFotis

.github/workflows/syntax-checks.yaml

@@ -47,3 +47,18 @@ jobs:
           BASE_BRANCH: ${{ github.base_ref }}
           MERGE_BRANCH: ${{ github.ref }}
         run: ./.github/workflows/pull-request-check-cpplint.sh
+
+  # This job should take about a minute (est)
+  check-rustfmt:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout CBMC repository 
+        uses: actions/checkout@v3
+      - name: Install latest stable Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+            toolchain: stable
+            override: true
+            components: rustfmt, clippy
+      - name: Run `cargo fmt` on top of Rust API project
+        run: cd src/libcprover-rust; cargo fmt --all -- --check