feat(eslint-plugin): [ban-types] add NonNullable suggestion and allow custom suggestions

[NotWoods]

PR Checklist

• Addresses an existing open issue: fixes Enhancement: [ban-types] Suggest NonNullable<unknown> as an alternative for {} and Object #6486 and fixes Enhancement: [ban-types] Add suggest option to types #6875
• [/] That issue was marked as accepting prs (will revert if the issue is rejected)
• Steps in Contributing were taken

Overview

This PR adds NonNullable<unknown> to the list of alternatives for Object and {}, and introduces suggestions to automatically replace those types with NonNullable<unknown>.

[typescript-eslint]

Thanks for the PR, @NotWoods!

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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[nx-cloud]

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✅ Successfully ran 25 targets

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

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[codecov]

Codecov Report

Merging #6876 (e9fcabd) into main (f0f83ce) will increase coverage by 0.00%.
The diff coverage is 100.00%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6876   +/-   ##
=======================================
  Coverage   87.36%   87.37%           
=======================================
  Files         386      386           
  Lines       13190    13193    +3     
  Branches     3867     3868    +1     
=======================================
+ Hits        11524    11527    +3     
  Misses       1300     1300           
  Partials      366      366           

Flag	Coverage Δ
unittest	87.37% <100.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
packages/eslint-plugin/src/rules/ban-types.ts	100.00% <100.00%> (ø)

[JoshuaKGoldberg]

💯 looks great, thanks @NotWoods!