Checkout yosys with submodules for test-docs too

.github/workflows/test-docs.yml

@@ -29,7 +29,8 @@ jobs:
 
       - name: Checkout Yosys
         uses: actions/checkout@v3
-
+        with:
+         submodules: true
       - name: Build yosys
         shell: bash
         run: |