check formatting in ci

.github/workflows/ci.yaml

@@ -28,6 +28,19 @@ jobs:
           make STATIC_LLVM=1 test
       - name: Run self-compare
         run: make STATIC_LLVM=1 compare
+
+      - name: Check nph formatting
+        # Pin nph to a specific version to avoid sudden style differences.
+        # Updating nph version should be accompanied with running the new
+        # version on the fluffy directory.
+        run: |
+          VERSION="v0.5.1"
+          ARCHIVE="nph-linux_x64.tar.gz"
+          curl -L "https://github.com/arnetheduck/nph/releases/download/${VERSION}/${ARCHIVE}" -o ${ARCHIVE}
+          tar -xzf ${ARCHIVE}
+          git ls-files | grep .nim$ | ./nph
+          git diff --exit-code
+
       - name: Create distribution
         run: bash make-dist.sh
       - name: Update release