Enhancement list for VS insertion PR tagger

Pipeline: https://devdiv.visualstudio.com/DevDiv/_release?definitionId=3293

Enhancement list (thanks to Joey for helping think of these):
- [ ] Include VS Insertion PR URL in the issue body, noting that it is Microsoft only
- [ ] Collect all the inserted PR authors and add them as assignees to the issue or otherwise tag them in the issue
- [ ] Label the inserted PRs as `vs-inserted`
- [ ] Output the generated issue URL
- [x] Close issues automatically (via FabricBot) (https://github.com/dotnet/roslyn/pull/63040)
- [ ] Convert `Merge PR < >` links (generated if merged PR was a fast-forward) to use PR title instead
- [ ] Use a bot to generate PRs instead of individual credentials
- [ ] Mark insertions into other repos (e.g. dotnet/sdk repo for F#)
- [ ] Switch to using a single pipeline instead of multiple via yml file - https://docs.microsoft.com/en-us/azure/devops/pipelines/process/pipeline-triggers?view=azure-devops
- [ ] Switch to using OctoKit - https://octokitnet.readthedocs.io/en/latest/getting-started/
- [ ] Set milestone on PR for which VS version it went into

Start with the VS insertion PR tagger pipeline linked in the issue and review the unchecked enhancement list. The issue names the desired outcomes, including PR URLs, author tagging, labels, generated URLs, cross-repository insertions, pipeline consolidation, OctoKit, and milestones; done would require selecting and implementing a defined subset.

Written by the indexing model from the issue text.