feat(eslint-plugin): [prefer-optional-chain] use type checking for strict falsiness

[JoshuaKGoldberg]

BREAKING CHANGE:
Adds type checking to prefer-optional-chain

PR Checklist

• Addresses an existing open issue: fixes [eslint-plugin] Breaking: enable type information for prefer-optional-chain #4820
• That issue was marked as accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

Uses the type checker to skip reporting a complaint when the original expression includes a falsy value that isn't undefined.

Also adds a looseFalsiness flag to allow the old, faster behavior.

Streamlines the test file because autogenerated tests are giving me headaches.

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✅ Successfully ran 47 targets

• Node 18 - nx test eslint-plugin
• Node 14 - nx test eslint-plugin --coverage=false
• nx run-many --target=typecheck --all --parallel
• nx run-many --target=lint --all --parallel
• Node 18 - nx test eslint-plugin-internal
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• Node 18 - nx test type-utils
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• Node 18 - nx test parser
• Node 14 - nx test eslint-plugin-tslint --coverage=false
• Node 18 - nx run-many --target=build --all --parallel --exclude website --exclude website
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• Node 18 - nx test typescript-estree
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• Node 18 - nx test eslint-plugin-tslint
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• Node 14 - nx test utils --coverage=false
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• Node 14 - nx test parser --coverage=false
• Node 14 - nx test typescript-estree --coverage=false
• Node 14 - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 14 - nx run-many --target=build --all --parallel --exclude website --exclude website
• nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 14 - nx test eslint-plugin-internal --coverage=false
• Node 14 - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 14 - nx test scope-manager --coverage=false
• Node 14 - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 14 - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 14 - nx test type-utils --coverage=false
• Node 14 - nx test ast-spec --coverage=false
• Node 14 - nx run-many --target=build --all --parallel --exclude website --exclude website
• Node 14 - nx run-many --target=build --all --parallel --exclude website --exclude website
• nx run-many --target=build --all --parallel --exclude website --exclude website

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[typescript-eslint]

Thanks for the PR, @JoshuaKGoldberg!

typescript-eslint is a 100% community driven project, and we are incredibly grateful that you are contributing to that community.

The core maintainers work on this in their personal time, so please understand that it may not be possible for them to review your work immediately.

Thanks again!

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[codecov]

Codecov Report

Merging #6240 (8d847e3) into v6 (28a64b5) will decrease coverage by 0.03%.
The diff coverage is 80.95%.

Additional details and impacted files

@@            Coverage Diff             @@
##               v6    #6240      +/-   ##
==========================================
- Coverage   85.23%   85.21%   -0.03%     
==========================================
  Files         372      373       +1     
  Lines       12729    12738       +9     
  Branches     3783     3785       +2     
==========================================
+ Hits        10850    10855       +5     
- Misses       1499     1502       +3     
- Partials      380      381       +1     

Flag	Coverage Δ
unittest	85.21% <80.95%> (-0.03%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
packages/type-utils/src/isTypeIntrinsic.ts	0.00% <0.00%> (ø)
...s/eslint-plugin/src/rules/prefer-optional-chain.ts	95.80% <85.00%> (-1.68%)	⬇️

... and 1 file with indirect coverage changes

[JoshuaKGoldberg]

Lots of merge conflicts here, will need to fix up... eventually.

[nx-cloud]

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✅ Successfully ran 30 targets

• Node 18 - nx test eslint-plugin
• Node 14 - nx test eslint-plugin --coverage=false
• nx run-many --target=build --projects=website-eslint,website
• nx run-many --target=lint --parallel
• nx run-many --target=typecheck --parallel
• nx run integration-tests:test
• nx run types:build
• Node 18 - nx test typescript-estree
• Node 18 - nx test utils
• Node 18 - nx run types:build
• Node 18 - nx test visitor-keys
• Node 18 - nx test type-utils
• Node 14 - nx test typescript-estree --coverage=false
• Node 18 - nx test scope-manager
• Node 14 - nx test scope-manager --coverage=false
• Node 18 - nx test eslint-plugin-internal
• Node 18 - nx test ast-spec
• Node 14 - nx test eslint-plugin-tslint --coverage=false
• Node 14 - nx test utils --coverage=false
• Node 14 - nx test parser --coverage=false
• Node 14 - nx run types:build
• Node 18 - nx test eslint-plugin-tslint
• Node 18 - nx test parser
• Node 14 - nx test ast-spec --coverage=false
• Node 14 - nx test type-utils --coverage=false
• Node 14 - nx test eslint-plugin-internal --coverage=false
• Node 14 - nx test visitor-keys --coverage=false
• Node 14 - nx test repo-tools --coverage=false
• Node 18 - nx test repo-tools
• nx run-many --target=build --parallel --exclude=website --exclude=website-eslint

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[JoshuaKGoldberg]

Closing in favor of #6397. Woop!