Prerequisites checklist

• I have read the contributing guidelines.
• The team has reached consensus on the changes proposed in this pull request. If not, I understand that the evaluation process will begin with this pull request and won't be merged until the team has reached consensus.

What is the purpose of this pull request? (put an "X" next to an item)

[X] Bug fix

Tell us about your environment

• ESLint Version: v7.0.0-alpha.3
• Node Version: v12.14.0
• npm Version: v6.13.4

What parser (default, Babel-ESLint, etc.) are you using?

default

Please show your full configuration:

module.exports = {
    parserOptions: {
        ecmaVersion: 2015
    }
}

What did you do? Please include the actual source code causing the issue.

Online Demo

/*eslint operator-linebreak: ["error", "after", { "overrides": { "+": true } }]*/

What did you expect to happen?

ESLint to report invalid configuration on true. This value should be one of ["after", "before", "none", "ignore"].

What actually happened? Please include the actual, raw output from ESLint.

no warnings

What changes did you make? (Give an overview)

Fixed the schema for overrides in the operator-linebreak rule. The previous schema actually defined allowed enum for the value of a property named "anyOf" (which doesn't make sense).

Also fixed the documentation. This rule has two options, not one option that can be either string or object.

Is there anything you'd like reviewers to focus on?

This invalid configuration had specific behavior, different from the 4 valid options. It works mostly as "ignore", but it also disallows cases where linebreaks are on both sides of the specified operator. Nevertheless, this isn't documented and it doesn't look it was intentional.