ci: add docs job

.gitea/workflows/gentoo-utils.yml

@@ -139,3 +139,17 @@ jobs:
           meson setup -Dfuzz=enabled -Dtests=enabled -Dbuildtype=debugoptimized build
           meson format --check-only --recursive
           ninja rustfmt -C build
+
+  docs:
+    runs-on: brutalisk
+    needs: [build-oci-image]
+    container:
+      image: ${{ vars.REGISTRY_URL }}/${{ gitea.repository }}:${{ needs.build-oci-image.outputs.image_tag }}
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v5
+
+      - name: Build Documentation
+        run: |
+          meson setup -Ddocs=enabled docs
+          ninja rustdoc -C docs