Replace Class-Only Protocol from class to AnyObject

# Report

## A feature request

###  What do you want to add?

I want to replace **Class-Only Protocol** from `class` to `AnyObject`, because of the following points of view.

 https://forums.swift.org/t/class-only-protocols-class-vs-anyobject/11507/11
[Swift Documentation – Class-only Protocols](https://docs.swift.org/swift-book/LanguageGuide/Protocols.html#ID281)