Build documentation on Python 3.14 (#675)

Author: adamchainz

.readthedocs.yaml

@@ -6,7 +6,7 @@ version: 2
 build:
   os: ubuntu-24.04
   tools:
-    python: "3.13"
+    python: "3.14"
   jobs:
       pre_create_environment:
           - asdf plugin add uv