Array declaration sniff should account for places where WP expects mixed key/no-key arrays

[JDGrimes]

The array syntax sniff will report when an array has some values assigned specific keys and others not.

314 | WARNING | No key specified for array entry; first entry specifies key
| | (WordPress.Arrays.ArrayDeclaration)

This causes a problem where WordPress requires mixed arrays, as in the 'meta_query' argument for WP_Query:

$args = array(
    'post_type' => 'product',
    'meta_query' => array(
        'relation' => 'OR', // 'relation' key used to specify AND/OR, the rest are numeric
        array(
            'key' => 'color',
            'value' => 'blue',
            'compare' => 'NOT LIKE'
        ),
        array(
            'key' => 'price',
            'value' => array( 20, 100 ),
            'type' => 'numeric',
            'compare' => 'BETWEEN'
        )
    )
);
$query = new WP_Query( $args );

The sniff should probably ignore any key if its text is 'related'.

[westonruter]

It seems we should eliminate this warning from the sniff. There is actually no reference to a forbidden mixing of explicit keys and implied numerical keys in the WordPress Coding Standards: http://make.wordpress.org/core/handbook/coding-standards/php/

[shadyvb]

@westonruter Just commented that problematic warning in #204