Alter readthedocs to prep for building to build html, htmlzip, and pdf docs. (pallets#2950)

Author: Rowlando13

.readthedocs.yaml

@@ -1,10 +1,17 @@
 version: 2
+# Do not specify sphinx key here to be in full control of build steps.
+# https://docs.readthedocs.com/platform/stable/build-customization.html#extend-or-override-the-build-process
+
 build:
   os: ubuntu-24.04
   tools:
     python: '3.13'
-  commands:
-    - asdf plugin add uv
-    - asdf install uv latest
-    - asdf global uv latest
-    - uv run --group docs sphinx-build -W -b dirhtml docs $READTHEDOCS_OUTPUT/html
+  jobs:
+    install:
+      - echo "Installing dependencies"
+      - asdf plugin add uv
+      - asdf install uv latest
+      - asdf global uv latest
+    build:
+      html:
+        - uv run --group docs sphinx-build -W -b dirhtml docs $READTHEDOCS_OUTPUT/html