Code Quality: Correct return statement in WP_Query::setup_postdata().

This reflects that the method can return both `true` (success) and `false` (failure).

Follow-up to [32620], [34089], [44941].

Props huzaifaalmesbah, westonruter.
See #64238.

git-svn-id: https://develop.svn.wordpress.org/trunk@61727 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/class-wp-query.php

@@ -4816,7 +4816,7 @@ public function is_main_query() {
 	 * @global int     $numpages
 	 *
 	 * @param WP_Post|object|int $post WP_Post instance or Post ID/object.
-	 * @return true True when finished.
+	 * @return bool True on success, false on failure.
 	 */
 	public function setup_postdata( $post ) {
 		global $id, $authordata, $currentday, $currentmonth, $page, $pages, $multipage, $more, $numpages;
@@ -4826,12 +4826,12 @@ public function setup_postdata( $post ) {
 		}
 
 		if ( ! $post ) {
-			return;
+			return false;
 		}
 
 		$elements = $this->generate_postdata( $post );
 		if ( false === $elements ) {
-			return;
+			return false;
 		}
 
 		$id           = $elements['id'];