Document new YAML anchor support in workflows

[janbrasna]

Code of Conduct

• I have read and agree to the GitHub Docs project's Code of Conduct

What article on docs.github.com is affected?

docs/content/actions/tutorials/migrate-to-github-actions/manual-migrations/migrate-from-circleci.md

Line 54 in 7d10f72

CircleCI can reuse pieces of workflows with YAML anchors and aliases. {% data variables.product.prodname_actions %} supports the most common need for reusability using matrices. For more information about matrices, see [AUTOTITLE](/actions/using-jobs/using-a-matrix-for-your-jobs).

What part(s) of the article would you like to see updated?

It hints at anchors and aliases not being available, but they are now.

Additional information

The article above is just an example, I think that actions/runner#1182 should be celebrated by adding a nice piece of documentation embracing that change — and constructing a few nice examples where the anchor & alias makes sense in GHA workflows.

[Sharra-writes]

@janbrasna Thanks for opening an issue! I'll check in about what kind of priority this would have for our writers. It may end up with a "help wanted" tag to see if anyone from the community wants to pick it up, but we'll find out!

Edit: Sorry, didn't mean to close this. Almost dropped my laptop and hit some keys. 😅