add page start-forms.md
Grammar fix
add start-looking-ahead.md
pull origin
Remove unnecessary Markdown code characters.
Fix Markdown link to the Yii class.
Update MessageController.php

Fixed order of checking config `format` property
Merge pull request #4561 from maxlapko/patch-1

Update MessageController.php
test and docs to be clear about #4558
Better alias handling for Twig extension
Minor template engine doc enhancement
Added support for arbitrary operators to Query::filterWhere, added support for arbitrary operators to Sphinx extension
Removed unnecessary code
Simplified parameter check for buildSimpleCondition()
Fixes #4425: generate cookie validation keys in local config files.
Fixes #4571: ignore non-string attribute names for AttributeBehavior.
Added client-side image validation
Fix lines
Abort further validation if there are no files to validate
Fixes #4566: Added client validation support for image validator