ci.skip docs are misleading

Problem to solve

The documentation on skipping jobs via pipeline configuration states that

Alternatively, one can pass the ci.skip Git push option if using Git 2.10 or newer:

git push -o ci.skip

This is misleading. The -o syntax was only introduced in git 2.18. Only the --push-option= option was available since git 2.10.

Proposal

List both options with a note on availability, e.g.:

git push --push-option=ci.skip    # using git 2.10+
git push -o ci.skip               # using git 2.18+