Try 3.11 for the doc build instead of 3.13

Author: mdickinson

.github/workflows/test-documentation-build.yml

@@ -11,7 +11,7 @@ jobs:
     - name: Set up Python
       uses: actions/setup-python@v6
       with:
-        python-version: '3.13'
+        python-version: '3.11'
     - name: Install dependencies and local packages
       run: python -m pip install .[docs]
     - name: Build HTML documentation with Sphinx