Fixed typo [ci skip]

singular is more suited to
change to "check out"
e-mail => email, and subject/verb agreement
add punctuation
Remove duplicate configuration option for ActiveSupport [ci skip]

Fixes rails/rails#13732
`requies` => `requires`
`easiy` => `easy`
`framwork` => `framework`
Remove old comments about suppressing warnings.
Fixed spelling error: `extracetd` => `extracted`
Skips linked folder tests if symlink is invalid
Merge pull request #13980 from mellowi/skipping_linked_folder_tests_if_symlink_is_invalid

Skips linked folder tests if symlink is invalid
Merge pull request #13978 from Fortisque/kevin/validation_context_for_children

context in validation goes through has many relationship
Add missing test for response destructuring.
Remove outdated TODO from url_for test, this test was fixed in 900a2d30
Merge pull request #13981 from Fortisque/kevin/postgresql_reaper_threadsafe

Reaper has access to threadsafe active? call
use feature detection to decide which implementation to use

Decouple the code from the particular Ruby version.
Prevent [response].flatten from recursing infinitely.

Returning `self` from within the array returned by `to_ary`
caused this. Instead, we can just substitute another object.
It provides the `each` behavior required by the rack spec.
use File.exist? instead of File.exists?
Merge pull request #13983 from hsbt/remove-warning

use File.exist? instead of File.exists?