github/workflows: Standardise formatting of ruff.yml.

All the other workflow YAML files use vertical whitespace around top-level
items.

Also remove spurious comment, the features in the linked doc aren't
actually used in this workflow (any more?).

This work was funded through GitHub Sponsors.

Signed-off-by: Angus Gratton <angus@redyak.com.au>

.github/workflows/ruff.yml

@@ -1,6 +1,7 @@
-# https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-python
 name: Python code lint and formatting with ruff
+
 on: [push, pull_request]
+
 jobs:
   ruff:
     runs-on: ubuntu-latest