[docs] comments inside snippets + README pass (DOCS-CODE-012)

[mmacy]

Purpose

• Pushes code comments inside the named snippets so they're rendered on docs.
• Added DOCS-CODE-012 identifier to README
• Light edit pass on the README

ℹ️ Companion to tutorial content PR https://github.com/MicrosoftDocs/azure-docs-pr/pull/187725.

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

What kind of change does this Pull Request introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[x] Documentation content changes
[ ] Other... Please describe:

How to Test

N/A - no code changes made.

What to Check

Verify that the following are valid:

• README.md
• Code comments

Other Information

None.

[mmacy]

🚀 lgtm!

@ckittel Sweet! Are we going with the "merge yer own stuff" pattern on these repos, or do I need another approver?

[ckittel]

You should merge your own stuff. You're a responsible adult that got approval. You did the hard work to make the change, you get the satisfaction of making it live. Ship it. :)