CI: Run biome on its own config file

.github/workflows/build_docs.yaml

@@ -61,6 +61,8 @@ jobs:
             - name: Upgrade pip and install pipenv
               run: |
                   sudo apt-get install python3-pip pipenv
+            - name: Setup Biome CLI
+              uses: biomejs/setup-biome@v2                  
             - name: Remove docs from cache # Avoid stale docs
               run: |
                   rm -rf target/doc target/cppdocs api/node/docs
@@ -69,6 +71,8 @@ jobs:
               run: cargo fmt --
             - name: C++ format
               run: find -iname \*.h -o -iname \*.cpp | xargs clang-format -i
+            - name: Run biome for top-level json config itself
+              run: biome format biome.json
             - name: Suggest format changes
               uses: reviewdog/action-suggester@v1
               with: