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

Fixes: https://github.com/rails/rails/issues/17108.
Fixing documentation in JSON#from_json

Commit d67b289 introduced a tiny regression in the docs for #from_json,
true needs to be included when the root node is present.
Adding simple docs for ActionDispatch::Flash::FlashHash#to_session_value
adding nodoc to private methods
be more general with adapter name
Use web_console 2.0 for 4.2.0.rc1 release

This one replaces the notable web-console mentions in guide and the
default Gemfile.
Merge pull request #17728 from jcutrell/jcutrell/docs-to_session_value-for-pr

Adding simple docs for ActionDispatch::Flash::FlashHash#to_session_value
Merge pull request #17773 from gsamokovarov/mention-web-console-2.0-rc1

Use web_console 2.0 for 4.2.0.rc1 release
Use jquery-rails 4.0.0
Clarify where result goes, and supported formats of generate task.

[ci skip]
getting the location of the server
Merge pull request #17779 from dilpreet92/server_location

Getting the location of the server
:scissors:
Remove extra empty line
Merge pull request #17780 from arcz/patch-1

Remove extra empty line
Active Record change log pass [skip ci]
Use absolute_path of caller_locations to infer engine root

According to documentation `path` only returns file names. On MRI it's
not the case but it's likely a bug in MRI.
Refactor nested if
Merge pull request #17784 from bruno-/refactor-nested-ifs

Refactor nested if
Provide support for SQL Server connections with dbconsole using sqsh