docs: set site_url to fix broken 404 page on RTD

mkdocs.yml

@@ -1,6 +1,8 @@
 site_name: Stub Generator
 repo_url: https://github.com/Safe-DS/Stub-Generator
 repo_name: Safe-DS/Stub-Generator
+edit_uri: edit/main/docs/
+site_url: !ENV READTHEDOCS_CANONICAL_URL
 
 nav:
   - Home:

readthedocs.yml

@@ -4,13 +4,21 @@ build:
   os: ubuntu-22.04
   tools:
     python: '3.10'
-  jobs:
-    # https://docs.readthedocs.io/en/stable/build-customization.html#install-dependencies-with-poetry
-    post_create_environment:
-      - pip install poetry
-      - poetry config virtualenvs.create false
-    post_install:
-      - poetry install --with docs
+  commands:
+    - pip install poetry
+    - poetry config virtualenvs.create false
+    - poetry install --with docs
+    - cat mkdocs.yml
+    - mkdocs build --clean --site-dir $READTHEDOCS_OUTPUT/html --config-file mkdocs.yml
+# Once https://github.com/readthedocs/readthedocs.org/issues/8529 is fixed, replace the commands above with the
+# following to use the default RTD build steps again:
+#  jobs:
+#    # https://docs.readthedocs.io/en/stable/build-customization.html#install-dependencies-with-poetry
+#    post_create_environment:
+#      - pip install poetry
+#      - poetry config virtualenvs.create false
+#    post_install:
+#      - poetry install --with docs
 
 mkdocs:
   configuration: mkdocs.yml