Clarification follow-up to e2cce6cd [ci skip]

[skip ci]

Action Mailer change log pass [ci skip]

[skip ci]

It should not be used in applications

Fix format "Form Helpers" guide

The `"_tag"` was interpreted as the start of a italics.

Fix typo in Rails 4.2 release notes

Documentation regression in JSON#from_json

Allow authentication header to not have to specify 'token=' key.

Code style changes for various activerecord errors

be more general with adapter name

Add #record attribute to RecordNotFound and RecordDestroyed exceptions.

Use absolute_path of caller_locations to infer engine root

Active Record change log pass [skip ci]

Provide support for SQL Server connections with dbconsole using sqsh

This allows these exceptions to be handled generically in conjunction with RecordInvalid.

Refactor nested if

According to documentation `path` only returns file names. On MRI it's
not the case but it's likely a bug in MRI.

Remove extra empty line

Getting the location of the server

[ci skip]

Use web_console 2.0 for 4.2.0.rc1 release