Add frozen_string_literal

lib/mimemagic/overlay.rb

+# frozen_string_literal: true
 # Extra magic
 
 [['application/vnd.openxmlformats-officedocument.presentationml.presentation', [[0, "PK\003\004", [[0..5000, '[Content_Types].xml', [[0..5000, 'ppt/']]]]]]],

lib/mimemagic/tables.rb

 # -*- coding: binary -*-
+# frozen_string_literal: true
 # Generated from freedesktop.org.xml
 class MimeMagic
   # @private

script/generate-mime.rb

@@ -133,6 +133,7 @@ end
 magics = (common_magics.compact + magics).uniq
 
 puts "# -*- coding: binary -*-"
+puts "# frozen_string_literal: true"
 puts "# Generated from #{FILE}"
 puts "class MimeMagic"
 puts "  # @private"