Improve signature of random_bytes()

Author: staabm

resources/functionMap.php

@@ -9056,7 +9056,7 @@
 'radius_strerror' => ['string', 'radius_handle'=>'resource'],
 'rand' => ['int', 'min'=>'int', 'max'=>'int'],
 'rand\'1' => ['int'],
-'random_bytes' => ['string', 'length'=>'int'],
+'random_bytes' => ['non-empty-string', 'length'=>'positive-int'],
 'random_int' => ['int', 'min'=>'int', 'max'=>'int'],
 'range' => ['array', 'low'=>'int|float|string', 'high'=>'int|float|string', 'step='=>'int|float'],
 'RangeException::__clone' => ['void'],