improve zpp readme

README.PARAMETER_PARSING_API

@@ -59,7 +59,7 @@ Type specifiers
  h  - array (returned as HashTable*)
  H  - array or HASH_OF(object) (returned as HashTable*)
  l  - long (zend_long)
- L  - long, limits out-of-range numbers to LONG_MAX/LONG_MIN (zend_long)
+ L  - long, limits out-of-range numbers to LONG_MAX/LONG_MIN (zend_long, ZEND_LONG_MAX/ZEND_LONG_MIN)
  o  - object of any type (zval*)
  O  - object of specific type given by class entry (zval*, zend_class_entry)
  p  - valid path (string without null bytes in the middle) and its length (char*, size_t)