feat(eslint-plugin): [restrict-plus-operand] add allowAny option

[lonyele]

PR Checklist

• Addresses an existing issue: fixes [restrict-plus-operands] Allowing any for summands #386
• That issue was marked as accepting prs
• Steps in CONTRIBUTING.md were taken

Overview

It allows any to be used with the current implementation that stringType such as any, string, bigint, number are possible to be added, but not with invalid types.

1. I didn't introduce new warning messages because I couldn't think of good namings. I found that notNumbers catches all warnings thus used it here too.
2. While tidying up if/else statement, code became if with return style, but if the code with if/else looks better, I'll
   change it.
3. I reformatted docs to more recent style
4. I couldn't push the code to feat(eslint-plugin): [restrict-plus-operands] add allowAny option #901, so I made a new one(again, sorry about the previous pr)

[typescript-eslint]

Thanks for the PR, @lonyele!

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 Report

CI ran the following commands for commit 578fa4b. Click to see the status, the terminal output, and the build insights.

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Status	Command
	Node 12.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 12.x - nx test @typescript-eslint/eslint-plugin
	Node 12.x - nx test @typescript-eslint/eslint-plugin-internal
	Node 12.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 12.x - nx test @typescript-eslint/eslint-plugin
	Node 16.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 16.x - nx test @typescript-eslint/eslint-plugin
	Node 14.x - nx test @typescript-eslint/eslint-plugin-tslint
	Node 14.x - nx test @typescript-eslint/eslint-plugin
	Node 12.x - nx run-many --target=typecheck --all --parallel
	Node 12.x - nx test @typescript-eslint/parser
	Node 12.x - nx test @typescript-eslint/experimental-utils
	Node 12.x - nx test @typescript-eslint/scope-manager
	Node 12.x - nx test @typescript-eslint/visitor-keys
	Node 12.x - nx test @typescript-eslint/typescript-estree

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[codecov]

Codecov Report

Merging #4260 (578fa4b) into main (9f58eab) will increase coverage by 0.62%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main    #4260      +/-   ##
==========================================
+ Coverage   92.73%   93.36%   +0.62%     
==========================================
  Files         335      152     -183     
  Lines       11542     8064    -3478     
  Branches     3289     2593     -696     
==========================================
- Hits        10704     7529    -3175     
+ Misses        364      179     -185     
+ Partials      474      356     -118     

Flag	Coverage Δ
unittest	93.36% <100.00%> (+0.62%)	⬆️

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

Impacted Files	Coverage Δ
.../eslint-plugin/src/rules/restrict-plus-operands.ts	100.00% <100.00%> (ø)
packages/scope-manager/src/lib/dom.iterable.ts
packages/scope-manager/src/lib/dom.ts
packages/scope-manager/src/lib/es2021.ts
packages/scope-manager/src/lib/es5.ts
packages/scope-manager/src/lib/index.ts
...ckages/scope-manager/src/lib/webworker.iterable.ts
packages/scope-manager/src/lib/webworker.ts
...ages/scope-manager/src/referencer/ExportVisitor.ts
packages/scope-manager/src/lib/es2015.reflect.ts
... and 174 more

[JoshuaKGoldberg]

Super, thanks! ✨