ext/imap: Narrow return type to true

Those functions always return true as of PHP 8.0.

Author: Girgias

ext/imap/php_imap.stub.php

@@ -409,7 +409,7 @@ function imap_open(string $mailbox, string $user, #[\SensitiveParameter] string
 
     function imap_reopen(IMAP\Connection $imap, string $mailbox, int $flags = 0, int $retries = 0): bool {}
 
-    function imap_close(IMAP\Connection $imap, int $flags = 0): bool {}
+    function imap_close(IMAP\Connection $imap, int $flags = 0): true {}
 
     function imap_is_open(IMAP\Connection $imap): bool {}
 
@@ -445,13 +445,13 @@ function imap_fetchheader(IMAP\Connection $imap, int $message_num, int $flags =
 
     function imap_fetchstructure(IMAP\Connection $imap, int $message_num, int $flags = 0): \stdClass|false {}
 
-    function imap_gc(IMAP\Connection $imap, int $flags): bool {}
+    function imap_gc(IMAP\Connection $imap, int $flags): true {}
 
-    function imap_expunge(IMAP\Connection $imap): bool {}
+    function imap_expunge(IMAP\Connection $imap): true {}
 
-    function imap_delete(IMAP\Connection $imap, string $message_nums, int $flags = 0): bool {}
+    function imap_delete(IMAP\Connection $imap, string $message_nums, int $flags = 0): true {}
 
-    function imap_undelete(IMAP\Connection $imap, string $message_nums, int $flags = 0): bool {}
+    function imap_undelete(IMAP\Connection $imap, string $message_nums, int $flags = 0): true {}
 
     function imap_check(IMAP\Connection $imap): \stdClass|false {}
 
@@ -503,9 +503,9 @@ function imap_status(IMAP\Connection $imap, string $mailbox, int $flags): \stdCl
 
     function imap_mailboxmsginfo(IMAP\Connection $imap): \stdClass {}
 
-    function imap_setflag_full(IMAP\Connection $imap, string $sequence, string $flag, int $options = 0): bool {}
+    function imap_setflag_full(IMAP\Connection $imap, string $sequence, string $flag, int $options = 0): true {}
 
-    function imap_clearflag_full(IMAP\Connection $imap, string $sequence, string $flag, int $options = 0): bool {}
+    function imap_clearflag_full(IMAP\Connection $imap, string $sequence, string $flag, int $options = 0): true {}
 
     function imap_sort(IMAP\Connection $imap, int $criteria, bool $reverse, int $flags = 0, ?string $search_criteria = null, ?string $charset = null): array|false {}