ci(support-matrix): check the generation exit code

The `mdbook-cmdrun` preprocessor, which is used to render the table in
the book, cannot make the mdbook run fail in case of non-zero exit code,
so we check this separately in the lint step.

.github/workflows/main.yml

@@ -332,6 +332,9 @@ jobs:
       - name: typos
         uses: crate-ci/[email protected]
 
+      - name: Check the support matrix generation exit code
+        run: ./doc/gen_support_matrix_html.rs generate doc/support_matrix.yml /dev/null
+
       - name: Install mdbook and mdbook utils
         uses: taiki-e/install-action@v2
         with: