Auto correct rubocop offenses

Offenses:

railties/lib/rails/autoloaders.rb:1:1: C: [Corrected] Style/FrozenStringLiteralComment: Missing magic comment # frozen_string_literal: true.
module Rails
^
actionmailer/test/base_test.rb:917:1: C: [Corrected] Layout/EmptyLinesAroundBlockBody: Extra empty line detected at block body beginning.
actionmailer/test/base_test.rb:917:1: C: [Corrected] Layout/TrailingWhitespace: Trailing whitespace detected.
actionmailer/test/base_test.rb:917:5: C: [Corrected] Style/RedundantBegin: Redundant begin block detected.
    begin
    ^^^^^
actionmailer/test/base_test.rb:918:3: C: [Corrected] Layout/IndentationWidth: Use 2 (not 4) spaces for indentation.
      events = []
  ^^^^
actionmailer/test/base_test.rb:930:1: C: [Corrected] Layout/EmptyLinesAroundBlockBody: Extra empty line detected at block body end.
actionmailer/test/base_test.rb:930:1: C: [Corrected] Layout/TrailingWhitespace: Trailing whitespace detected.

1 files changed, 2 insertions, 0 deletions

diff --git a/railties/lib/rails/autoloaders.rb b/railties/lib/rails/autoloaders.rb
index 4b71f90c6b..b03499cf81 100644
--- a/railties/lib/rails/autoloaders.rb
+++ b/railties/lib/rails/autoloaders.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 module Rails
   module Autoloaders # :nodoc:
     class << self