Layout/LineContinuationSpacing applies to non-Ruby source (DATA section)

[Bo98]

The new Layout/LineContinuationSpacing cop incorrectly applies itself to text after __END__.

---

Expected behavior

The cop is not raised for non-Ruby code.

Actual behavior

The cop is triggered.

Steps to reproduce the problem

# frozen_string_literal: true

class ThisIsRubyCode
  def initialize
    puts "Hello"
  end
end

__END__
random text, such as a git diff           \
which should not be checked

RuboCop version

$ [bundle exec] rubocop -V
1.31.0 (using Parser 3.1.2.0, rubocop-ast 1.18.0, running on ruby 2.6.8 x86_64-darwin15)
  - rubocop-performance 1.14.2
  - rubocop-rails 2.15.0