Coding Standards: Use strict comparison in wp_count_attachments().

Follow-up to [54255].

Props aristath, poena, afercia, SergeyBiryukov.
See #62279.

git-svn-id: https://develop.svn.wordpress.org/trunk@59567 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/post.php

@@ -3390,7 +3390,8 @@ function wp_count_attachments( $mime_type = '' ) {
 	);
 
 	$counts = wp_cache_get( $cache_key, 'counts' );
-	if ( false == $counts ) {
+
+	if ( false === $counts ) {
 		$and   = wp_post_mime_type_where( $mime_type );
 		$count = $wpdb->get_results( "SELECT post_mime_type, COUNT( * ) AS num_posts FROM $wpdb->posts WHERE post_type = 'attachment' AND post_status != 'trash' $and GROUP BY post_mime_type", ARRAY_A );