[prototype runtime] Find redefined methods

[ksss]

Since methods redefined in subclasses may have different types, I believe we should display the prototypes of such redefined methods when using --todo.

Repro

# sample.rb
class A
  def foo; 1; end
end
class B < A
  def foo; 'a'; end
end

# sample.rbs
class A
  def foo: () -> Integer
end
class B < A
end

$ bundle exec rbs -I sample.rbs prototype runtime --require-relative sample.rb --todo B

Actual

class B < ::A
end

Expect

class B < ::A
  def foo: () -> untyped
end

[soutaro]

👍