* Indent after private/protected
* Ruby >= 1.9 syntax for hashes
* Prefer method { do_stuff } instead of method{do_stuff} for single-line blocks.

[ci skip]

This reverts commit 70d6e16f, reversing
changes made to ea4db3bc.

Seems to be a code merge done by mistake.

for blank?

* it's Action Mailer not ActionMailer
* it's Action Pack not ActionPack
* it's Active Support not ActiveSupport

/cc @fxn

/cc @fxn

Added documentation for beginning_of_minute and end_of_minute to Active Support Core Extensions guide

instance_variable_names remains for internal use, but it's not that useful for the users anymore

Don't use:
* Time.time_with_datetime_fallback
* Time.utc_time
* Time.local_time

There's no reason for guides to reference old behaviors. They should
be current as of the versions of Rails that they ship with, and including
older information just clutters thing.

I discussed this change with @fxn and he agrees.

Patched Marshal#load to work with constant autoloading (active_support/dependecies.rb) (issue #8167)

ActiveRecord::Observer was extracted into a separate gem so it
should not be referenced anymore (see https://github.com/rails/rails/commit/ccecab3)

We have three or four different introduction sentences to the guides.
After this commit, we use the same one everywhere.