[no-unreachable] and [no-unused-label] are handled inconsistently

[amayer42]

• I have tried restarting my IDE and the issue persists.
• I have updated to the latest version of the packages.
• I have read the FAQ and my problem is not listed.

Repro

{
  "extends": [
    "eslint:recommended",
    "plugin:@typescript-eslint/eslint-recommended",
    "plugin:@typescript-eslint/recommended"
  ]
}

function test() {
  return 'test';
  const a = 'a';
}

Label: {
  test();
}

Expected Result

The unreachable code and the unused label should both be handled by either TypeScript or by the eslint:recommended rules.

Actual Result

With default settings, the unused label is flagged as invalid both by VSCode (dims the text and provides the reason: "Unused label.ts(7028)") and when linting ("'Label:' is defined but never used.eslint(no-unused-labels)"). The unreachable code is only flagged as invalid by VSCode (dims the text and provides the reason: "Unreachable code detected.ts(7027)").

Additional Info

Based upon my understanding of the eslint-recommended, any rule that is handled by the TypeScript compiler by default should be disabled by this config. I'm curious if this stance holds even for the rules above that are not considered errors in TypeScript by default.

• https://www.typescriptlang.org/tsconfig/#allowUnreachableCode
• https://www.typescriptlang.org/tsconfig/#allowUnusedLabels

It might be good to document that stance a bit better. That seems like the decision from #1041, though it seems that nothing was ever done to enhance the documentation.

Documentation aside, I think that it at least makes sense to be as consistent as possible with how the eslint-recommended config handles rules that overlap with TypeScript.

Versions

It's worth pointing out along with these versions that as of v5.19.0, the rules in question still have the same settings as in my local versions

package	version
@typescript-eslint/eslint-plugin	4.3.0
@typescript-eslint/parser	4.3.0
TypeScript	4.0.5
ESLint	7.31.0
node	14.19.0

[JoshuaKGoldberg]

Once #4706 is added with overhauled preset config docs, it'd be good to document this a bit more. +1