doc: make CI fail if the documentation generation raise warnings

.github/workflows/tests.yaml

@@ -108,4 +108,4 @@ jobs:
       - run: |
           export TZ=UTC
           uv sync --group doc
-          uv run sphinx-build doc build/sphinx/html
+          uv run sphinx-build doc build/sphinx/html --fail-on-warning

.gitlab-ci.yml

@@ -78,5 +78,5 @@ doc:
   stage: test
   script:
     - uv sync --group doc
-    - uv run sphinx-build doc build/sphinx/html
+    - uv run sphinx-build doc build/sphinx/html --fail-on-warning
     - uv cache prune --ci

doc/conf.py

@@ -56,7 +56,6 @@ exclude_patterns = []
 pygments_style = "sphinx"
 todo_include_todos = True
 toctree_collapse = False
-
 intersphinx_mapping = {
     "python": ("https://docs.python.org/3", None),
     "authlib": ("https://docs.authlib.org/en/latest", None),

pyproject.toml

@@ -239,7 +239,7 @@ basepython = ["python3.10"]
 [tool.tox.env.doc]
 dependency_groups = ["doc"]
 commands = [
-    ["sphinx-build", "--builder", "html", "doc", "build/sphinx/html"],
+    ["sphinx-build", "--builder", "html", "--fail-on-warning", "doc", "build/sphinx/html"],
     ["sphinx-build", "--builder", "man", "doc", "build/sphinx/html"],
 ]