Use Read the Docs native uv support (#697)

Per https://about.readthedocs.com/blog/2026/04/uv-native-support/.

Author: adamchainz

.readthedocs.yaml

@@ -7,15 +7,13 @@ build:
   os: ubuntu-24.04
   tools:
     python: "3.14"
-  jobs:
-      pre_create_environment:
-          - asdf plugin add uv
-          - asdf install uv latest
-          - asdf global uv latest
-      create_environment:
-          - uv venv "${READTHEDOCS_VIRTUALENV_PATH}"
-      install:
-          - UV_PROJECT_ENVIRONMENT="${READTHEDOCS_VIRTUALENV_PATH}" uv sync --frozen --group docs
+
+python:
+  install:
+    - method: uv
+      command: sync
+      groups:
+        - docs
 
 sphinx:
   configuration: docs/conf.py