Steps to reproduce the problem

# Foo
class Foo < Set
  def initialize
    super
    add?('Default')
  end
end

pp Foo.new

Actual behavior

Predicate method names should end with `?`. [Naming/PredicateMethod]

Suggested behavior

No warning.

1. No other types are complained about. Thus it seems understood that they are statements, never return values.
2. It seems the root cause is a simple oversight of not excluding initialize when implementing the cop.

RuboCop version

ruby      2025-08-01 30a20bc16
rubocop   2025-08-12 c34098ee0
System Version: macOS 15.6 (24G84)
Model Identifier: MacBookAir10,1