Scheduled pipelines improvements

[blag]

This PR fixes a few small things:

• A Markdown syntax omission
• Indent the code blocks so they render at the same indent depth as the list items in which they appear

It also improves the conversion examples by also including the branch filtering criteria, converted to workflow filtering syntax.

Previously the converted examples did not include workflow filtering for the branch filtering present in the previous trigger syntax:

      daily-run-workflow:
        triggers:
          - schedule:
              # Every day, 0421Z.
              cron: "21 4 * * *"
              filters:      # <--
                branches:   # <--
                  only:     # <--
                    - main  # <-- These parts

Reviewers please pay special attention to the last example, because I'm not 100% sure if this is supported filtering syntax:

when:
  and:
    - not:
        equal: [ scheduled_pipeline, << pipeline.trigger_source >> ]
    - equal: [ "main", << pipeline.git.branch >> ]

If I have missed the detailed documentation on the when and unless clauses, please point me to them.

Edit: Completeness and grammar.

[blag]

Is this getting merged anytime soon?