Use return types

Author: mikeSimonson

ext/date/php_date.stub.php

@@ -146,8 +146,7 @@ public static function __set_state(array $array);
     /** @return DateTime */
     public static function createFromImmutable(DateTimeImmutable $object);
 
-    /** @return DateTime */
-    public static function createFromInterface(DateTimeInterface $object);
+    public static function createFromInterface(DateTimeInterface $object): DateTime;
 
     /** @return DateTime|false */
     public static function createFromFormat(
@@ -190,8 +189,7 @@ public static function __set_state(array $array);
     /** @return DateTimeImmutable */
     public static function createFromMutable(DateTime $object);
 
-    /** @return DateTimeImmutable */
-    public static function createFromInterface(DateTimeInterface $object);
+    public static function createFromInterface(DateTimeInterface $object): DateTimeImmutable;
 
     /** @return DateTimeImmutable|false */
     public static function createFromFormat(