Add rake test description

No behavior change
clarify singular and plural routes

Found the wording on line 158 somewhat confusing. Added short example to clarify.
Update guides/source/active_record_querying.md

Fix missing `ORDER BY id ASC` for Client.first(2);
Uppercase the little y in the SQL equivalent of the Client.last(2).
Fix bug in code example from layouts and rendering guide

The code in 2.3.2 assumed that render has an alert option like
redirect_to to create a flash alert message, but it doesn't.
Corrected link anchor and added colons for continuity
improve grammar describing ActionDispatch::Cookies::CookieJar#delete
improve grammar describing ActionDispatch::Cookies::CookieJar#delete
Update the "upgrading" guide for people coming from 3.0 and 3.1. The latest versions for 3.1 and 3.2 are now 3.2.12 and 3.1.11 respectively.
Typo fix.
Removed template_root as a configuration option

Removed template root from actionmailer configuration options as it seems to have been pulled out completely in favor of explicit definition via template_path / template_name.
Link is not relevant anymore

Cannot find the screencast on the internet, guess it was removed
Added documentation for beginning_of_minute and end_of_minute to Active Support Core Extensions guide
Wrap `around_action` word with <code> tag
Update guide doc to use migration shortcuts
BELONGS TO ASSOCIATION | Typo fix
Typo fix
Fix #9360 regression in content_for
Fix deletion of empty directories:

1. When comparing the directory to delete against the top level
   cache_path, use File.realpath to make sure we aren't comparing two
   unequal strings that point to the same path. This occurs, for
   example, when cache_path has a trailing slash, which it does in the
   default Rails configuration. Since the input to
   delete_empty_directories never has a trailing slash, the comparison
   will never be true and the top level cache directory (and above) may
   be deleted. However…

2. File.delete raises EPERM when trying to delete a directory, so no
   directories have ever been deleted. Changing the code to Dir.delete
   fixes that.
cache_key consults updated_on timestamp if present

- Extract max timestamp retrieval for cache_key
- Update changelog for cache_key changes
Merge pull request #9441 from rubys/master

This is a small thing, motivated by https://github.com/rails/rails/issues/9419