title: Ruby: What does the comment "frozen_string_literal: true" do?
body: <p>This is the <code>rspec</code> binstub in my project directory.</p>
  
  <pre><code>#!/usr/bin/env ruby
  begin
    load File.expand_path("../spring", __FILE__)
  rescue LoadError
  end
  # frozen_string_literal: true
  #
  # This file was generated by Bundler.
  #
  # The application 'rspec' is installed as part of a gem, and
  # this file is here to facilitate running it.
  #
  
  require "pathname"
  ENV["BUNDLE_GEMFILE"] ||= File.expand_path("../../Gemfile",
    Pathname.new(__FILE__).realpath)
  
  require "rubygems"
  require "bundler/setup"
  
  load Gem.bin_path("rspec-core", "rspec")
  </code></pre>
  
  <p>What is this intended to do?</p>
  
  <pre><code># frozen_string_literal: true
  </code></pre>