HashWithIndifferentAccess#select working as intended

Before this commit, #reject returned a HashWithIndifferentAccess,
whereas #select returned a Hash. Now #select also returns a
HashWithIndifferentAccess.
Refactored ActiveRecord `first` method to get rid of duplication.
rename method `find_first_records` to `find_first_with_limit`
Added an example of the query without except before the example with except
Merge pull request #10937 from prathamesh-sonpatki/except_example

Added an example of the query without except before the example with except
Use DatabaseTasks.env instead of Rails.env in databases.rake
Properly namespace DatabaseTasks
Merge pull request #10898 from dmitry/find_first_refactor_duplication

Refactored ActiveRecord `first` method to get rid of duplication.
Merge pull request #10740 from mrsimo/hash-with-indifferent-access-select

HashWithIndifferentAccess#select working as intended
Add CHANGELOG entry for #10740

[ci skip]
valid_app_const? -> valid_const?
Changing const_regexp to check for constant name.

We need to return Regexp.escape(camel_cased_word)
if the split is blank.
Merge pull request #10946 from arunagw/build_fix_for_object_const_get_nil

We need to check exception name to be nil
Merge pull request #10950 from appscape-forks/fix-wrong-method-name

Fix wrong method name
Fix AS changelog [ci skip]