improve readability
change merge to merge!
move tests for NamedScope and DefaultScope under test/cases/scoping/

The scoping/default.rb and scoping/named.rb got moved under scoping/ in
commit 2b22564c4efaa63d4bbc006762838c4025c1bdca,
but the tests never did.
rename named_scope_test.rb to a proper file name

The file name should be name_scoping_test.rb and the class should be
`NamedScopingTest` according to ActiveRecord::Scoping::Name
split relation_scoping_test.rb's default scoping tests into another file
Refactored to remove unnecessary setup
fix some typos in AS
Merge pull request #10007 from vipulnsward/fix_AS_typos

Fix some typos in AS
Merge pull request #9997 from vipulnsward/hash_destructive_merge

Change merge to merge! to avoid creating new objects
Merge pull request #10003 from tkhr/refactor-scoping-test-files

Reorganize scoping test files
Merge pull request #10004 from choudhuryanupam/master

Refactored to remove unnecessary setup
Use last released version of thor
Minor reviews in AR changelog [ci skip]
Merge pull request #9991 from Passionate/patch-1

improve readability
Use new hash style in doc examples [ci skip]
Fix code examples indent in new index options docs [ci skip]
Make docs a little bit more consistent with colons [ci skip]
Do not calculate values if they are not going to be used

When building the indexes list in PostgreSQL, IndexDefinition objects
are only created if the query for the related attributes really returns
something matching the attributes.

In case it does not, the variables for building the definition objects were
being created but not used.
Improve changelog entry for ActiveModel::Errors#full_messages_for [ci skip]

Add a working example of how to use this new method.
Review some tests from AMo::Errors to remove "should" usage

Also remove duplicated tests for Errors#as_json and minor improvements
in some tests.