Fix wrong IntlDateFormatter format signature

Author: Alfred Bez

resources/functionMap.php

@@ -5515,7 +5515,7 @@
 'IntlCodePointBreakIterator::getLastCodePoint' => ['int'],
 'IntlDateFormatter::__construct' => ['void', 'locale'=>'?string', 'datetype'=>'?int', 'timetype'=>'?int', 'timezone='=>'null|string|IntlTimeZone|DateTimeZone', 'calendar='=>'null|int|IntlCalendar', 'pattern='=>'string'],
 'IntlDateFormatter::create' => ['IntlDateFormatter|false', 'locale'=>'?string', 'datetype'=>'?int', 'timetype'=>'?int', 'timezone='=>'null|string|IntlTimeZone|DateTimeZone', 'calendar='=>'int|IntlCalendar', 'pattern='=>'string'],
-'IntlDateFormatter::format' => ['string', 'args'=>''],
+'IntlDateFormatter::format' => ['string|false', 'args'=>''],
 'IntlDateFormatter::formatObject' => ['string', 'object'=>'object', 'format='=>'mixed', 'locale='=>'string'],
 'IntlDateFormatter::getCalendar' => ['int'],
 'IntlDateFormatter::getCalendarObject' => ['IntlCalendar'],