Add custom processor to lint JSDoc codeblocks

[som-sm]

A common task when reviewing PRs is manually checking JSDoc codeblocks for issues like missing semicolons, broken indentation, use of double quotes etc. This PR addresses that by adding linting to JSDoc codeblocks. They will now be linted just like our regular TS files, so any lint errors in JSDoc codeblocks will be caught automatically, and auto-fixable errors can be fixed just like regular auto-fixable errors.

demo.mov

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Common lint errors:

• Use of interface instead of type
  

• Incosistent spacing
  

• Incorrect quotes
  

• Use of T[] for non-simple types.

  

• Missing semicolon
  

• Use of spaces instead of tabs

  

These are just a few examples. Otherwise, all the rules (except the ones explicitly disabled) that apply to our TS source files apply to JSDoc codeblocks as well.

[som-sm]

This bump is needed because the number of files in the TS program has increased from 792 to 839. The default limit seems to be 4GB, and increasing it by 1GB works fine.

The extra files come from the new typescript-eslint package added in this PR.

# main
npx tsc --listFilesOnly | wc -l # 792

# feat/lint-jsdoc-codeblocks
npx tsc --listFilesOnly | wc -l # 839

If this is a problem, we can disable allowJS in tsconfig.json for now, which will bring down the files to 514 and then come back to this separately.

# "allowJS": false
npx tsc --listFilesOnly | wc -l # 514

[som-sm]

This config file is used to lint the test cases. And, this is present inside the repo instead of the temp directory because it needs certain imports.

[som-sm]

It would have been cleaner if this were done using snapshot testing, it would have moved the outputs to a separate snapshot file. But t.assert.snapshot is not available in Node 20, and we currently run the tests on Node 20.

[som-sm]

Added comments wherever I felt it needed some explanation.

[som-sm]

@sindresorhus This PR is ready for review now!

• All the changes within the source directory are inside JSDoc example codeblocks only. Most of these changes were auto-fixable, and the ones that weren't are captured separately in this commit.
• Unlike the validate-codeblocks lint rule, this processor applies the lint rules to all JSDoc codeblocks, not just the exported ones. This seems fine and makes sense, since it's nice to catch lint errors even in non-exported JSDoc codeblocks.

[sindresorhus]

Yay! So nice to have this automatically enforced too 🎉