Add error message for including nokogiri in Gemfile for rake doc:guides [ci skip]

- When `rake doc:guides` is run from applications, it complains for
  presence of redcarpet if it not present in Gemfile
- Similarly it should complain about nokogiri
Use infinity const
Stray nodoc causes rest of file not parsed [ci skip]
Merge pull request #11978 from edogawaconan/fix_doc_collection_proxy

Stray nodoc causes rest of file not parsed [ci skip]
Add examples of AR order method's hash notation to Rails Guide [ci skip]
Merge pull request #11967 from jetthoughts/add_action_controller_bug_report_template

Added bug report template for ActionController
Merge pull request #11943 from suginoy/ar-order-notation

Add examples of AR order method's hash notation to Rails Guide [ci skip]
Merge pull request #11976 from etehtsea/inf

[PG adapter] Use infinity const
Display exceptions in text format for xhr request
Merge pull request #11971 from freerunningtechnologies/dynamic_respond_to

Performance regression in AR::Base.respond_to?
Creating options for schema dumper.

These options make it easier to change the config from
ActiveRecord::Base to use something else inside of the SchemaDumper.
Making proper_table_name take in options.

The options will specify the prefix and the suffix. Also, I'm moving the
method to be an instance method on the +Migration+ instance. This makes more
sense than being a class method on the +Migrator+ class because the only
place that uses it is on a +Migration+ instance (in a method_missing
hook). The logic for the Migrator shouldn't be doing any work to
calculate the table name, it should be the Migration itself.

Also made some small indentation fixes.
Add a note about edge guides in the feedback section[ci skip]
Merge pull request #11991 from prathamesh-sonpatki/note-edge-guides

Add a note about edge guides in the feedback section [ci skip]
remove unused instance variable
Merge pull request #11994 from rajcybage/fix_instance

remove not used instance variable
Fix typo in file path, should include extension.
Adds Akshay Surve to Rails Guides credits list

I had written the original guide for "A Guide to Testing Rails
Applications". The current documents maintains the same structure and
examples I had drafted albeit with some minor changes to keep up with
newer version of Rails.

Older version which had credits included:
http://guides.rubyonrails.org/v2.3.11/testing.html

Github lifo/docrails History:
https://github.com/rails/rails/commits/ff359af86505b4d317b7467e7f79aa2ef2c5e795/railties/doc/guides/source/testing_rails_applications.txt
Merge pull request #11996 from semaperepelitsa/master

Docs: fix typo in file path, should include extension. [ci skip]
cleans the guides sources from fancy non-ASCII stuff