Output relevant URLs in GitHub Actions logs.

[desrosj]

Several GitHub Actions workflows are responsible for performing tasks against pull requests in response to certain actions. However, because of how actions run, it's not easy to determine what was performed by each workflow run. This is compounded by the fact that events such as workflow_run and workflow_dispatch don't always list a branch, pull request, or commit as context.

A few examples:

• The reusable-cleanup-pull-requests.yml workflow closes pull requests that mention a given ticket noted as Fixed in a commit message. The SVN changeset, ticket, and the pull requests closed on GitHub should be noted and linked.
• The failed-workflow.yml workflow automatically reruns a workflow once to help rule out network-related failures. The workflow being rerun should be noted and linked to.
• The props-bot.yml workflow collects props for a given pull request. The pull request should be noted and linked.
• The commit-built-file-changes.yml workflow commits any missed changes to built files under version control back to a pull request. The pull request being updated should be noted and linked to.

Note: This list is not all inclusive. Each workflow should be examined for any details that could be helpful to output into each workflow run log.

Trac ticket: https://core.trac.wordpress.org/ticket/64299

## Summary
Adds logging output to GitHub Actions workflows to display relevant URLs in workflow run logs. This improves visibility into what each workflow is performing.

## Changes Made

• reusable-cleanup-pull-requests.yml: Outputs SVN changeset URL, Trac ticket URLs, and pull request URLs being closed
• failed-workflow.yml: Outputs the workflow run URL being rerun, along with branch and PR information
• props-bot.yml: Outputs the pull request URL being processed
• commit-built-file-changes.yml: Outputs the source workflow run URL and pull request/branch information

## Testing Instructions

1. The workflow-lint action will automatically validate YAML syntax
2. After merge, monitor workflow runs to see the new log outputs
3. Example workflows to check:
   • Props Bot: ​https://github.com/WordPress/wordpress-develop/actions/workflows/props-bot.yml
   • Failed Workflow: ​https://github.com/WordPress/wordpress-develop/actions/workflows/failed-workflow.yml