[docs] Removed respond_with documentation as it was deprecated and removed from Rails [ci-skip]

of respond_to. respond_with was moved into the responders gem and deprecated
inside rails, so there is no need to mention it within rails itself.

We introduced a performance hit by adding an additional iteration
through a model's attributes on creation. We don't actually need the
values from `Result` to be a hash, we can separate the columns and
values and zip them up ourself during the iteration that we have to do.

Cleanup loaded features and constants after dependency tests.

copy reflection_scopes’s unscoped value when building scope for preloading

Add test/jobs files in `rake stats`

As we are no more displaying frameworks

[ci skip]

Remove skip-gems from 4-2 release notes [ci skip]

rake db:create shows underlying error message.

Remove unused duplicated method `add_column_position` from AbstractMysqlAdapter.

- This option was removed in https://github.com/rails/rails/commit/bf17c8a531bc80.
- [ci skip]

Removed the unused require of proxy_object

- Reference : https://github.com/rails/rails/pull/17493#issuecomment-61739359
- Duration stopped inheriting from ProxyObject in https://github.com/rails/rails/pull/16574

Fix broken string_ext_test due to change in timezone

- Russian time was changed to UTC+3 from UTC+4 recently. This broke the
  string_to_ext test.

[ci skip] fix `config.assets.digest` default value

Fixup spelling and grammar in 4.2 guides

Capitalize CSS, SQL

Change spelling of favour to favor - updated for consistency,
the rest of the document uses "favor".

Grammar / spelling pass

* 17106:
  add lib to $LOAD_PATH on application inhertence. fixes #17106
  add a test for #17106

Mention that articles resource should be added by user in getting started guide

Fixes #17507 [ci skip]

[ci skip]

Added SchemaDumper support for tables with jsonb columns

Move DebugExceptions#traces_from_wrapper to ExceptionWrapper

update rails version for earlier releases in edgeguides [ci skip]

minor docs change [ci skip]

added example for hash slice method [ci skip]