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`
Fix grammar of internal comment and modify it's location
Specify what #starts_with? we're talking about. Also added a note what
kind of exception we should expect for this internal comment.
docs, link MySQL manual for multi column indexes. [ci ckip].

Closes #9131.
Use full-length version of multiple from c7abc51
adds a section about booleans in the API guidelines [ci skip]
Fixed a grammatical error in Booleans section of API documentation guide
from e1e17a5
Merge branch 'master' of github.com:rails/docrails

Conflicts:
	guides/source/active_record_validations.md
	guides/source/api_documentation_guidelines.md
	guides/source/configuring.md