Fix regular expression for commit message containing -draft

What does this MR do and why?

Fix the documentation on https://docs.gitlab.com/ee/ci/yaml/workflow.html where it said that the regular expression /-draft$/ would match commits that contain -draft. I think the expression should instead be /-draft/ (without the $).

Screenshots or screen recordings

When using the old regex with /-draft$/, jobs are run for all commits, even if they do contain -draft:

With the updated regex (without the $), commits that contain -draft don't create jobs:

How to set up and validate locally

1. Create a new .gitlab-ci.yml file in a repository.
2. Add the following contents to the file:

workflow:
  rules:
    - if: $CI_COMMIT_MESSAGE =~ /-draft/
      when: never
    - when: always
publish:
  image: node:latest
  stage: deploy
  script: echo "Hello"

3. Commit your changes.
4. Create another commit with a commit message containing -draft and push.
5. Check in Gitlab whether your pipeline has been run for the new commit. It should not have been run.
6. Create another commit that doesn't contain -draft, push and check whether your pipeline has been run. It should have run.

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.