fix doc code according to yii2 core code style (When instantiating class it should be new MyClass(); instead of new MyClass;.)

Text amended as "A new method" was referring to two. CHanged the text to "New methods".

worked though all the guide files adjusted structure and
added some missing does

Control statements based on the if and elseif constructs must have a single space before the opening parenthesis of the conditional and a single space after the closing parenthesis.

* Documentation corrections for data population and quoting names in SQL query

This reverts commit 9a5ca995.