Custom formatter guide recommends use of an API marked as private

[sambostock]

The custom formatter guide says to use BaseFormatter:

Creating a Custom Formatter

To implement a custom formatter, you need to subclass RuboCop::Formatter::BaseFormatter and override some methods, or implement all formatter API methods by duck typing.

Please see the documents below for more formatter API details.

• RuboCop::Formatter::BaseFormatter
• RuboCop::Cop::Offense
• Parser::Source::Range

However, the class is listed as private API

Class: RuboCop::Formatter::BaseFormatter _Private

Overview

Warning
This class is part of a private API. You should avoid using this class if possible, as it may be removed or be changed in the future.

Abstract base class for formatter, implements all public API methods.

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Expected behavior

Either the guide should recommend another approach, or the API documentation should not describe the formatter as private.

Actual behavior

The guide and API docs conflict.

Steps to reproduce the problem

Visit current (January 12 2023) versions of links above.

RuboCop version

Not really relevant, since it's docs. Current SHAs of master branches are:

• rubocop/rubocop@c11a8b1421
• rubocop/docs.rubocop.org@471f20505c

[koic]

This is an erroneous @api private mark for RuboCop::Formatter introduced in #11294. So the guide is correct. I've fixed it by b1fb518.