Removed use of type checker from completed-docs

[JoshuaKGoldberg]

Uses tsutil's getJsDoc instead.

PR checklist

• Addresses an existing issue: Fixes Stop using the type checker in completed-docs #3376. Fixes New completed-docs "tags" property doesn't work with single-line doc comments #3365.
• New feature, bugfix, or enhancement
  • Includes tests
• Documentation update

Overview of change:

Makes completed-docs an untyped rule by removing usages of the TSLint program. It instead uses tsutils's getJsDoc.

CHANGELOG.md entry:

[enhancement] Made completed-docs an untyped rule
[bugfix] Fixed single-line comment parsing for completed-docs

[JoshuaKGoldberg]

(will look at version-specific failures soon - will also add test case for mismatched names in accessors) ✔️

[suchanlee]

whats the status of this PR?

[JoshuaKGoldberg]

I think I've addressed all of @ajafff's feedback. It's been through a few merges.

Also, some amusing errata: this also fixes the TS 2.8 issue with the [Symbol.iterator]() {} doc comment.

[buu700]

Any recent updates on this? (Very eager to have back my completed-docs that hasn't worked since December 2016!) Would it be worth merging #3841 as a stopgap until this is completely ready to go?

[johnwiseheart]

This looks reasonable to me. Theres a couple of new issues springing up from completed-docs (#4399, #4398, #4396), so I'd love to get this out before working on them with the hope that it might help to fix them.

stale