Fix typo in Quickstart docs

Author: mikhailpashkov

doc/quickstart.rst

@@ -249,7 +249,7 @@ using a library similar to :mod:`python:argparse`.
     Unlike the :mod:`python:argparse` module, :meth:`~reqparse.RequestParser.parse_args`
     returns a Python dictionary instead of a custom data structure.
 
-Using the :class:`~reqparse.RequestParser` class also gives you sane error messages for free.
+Using the :class:`~reqparse.RequestParser` class also gives you same error messages for free.
 If an argument fails to pass validation,
 Flask-RESTX will respond with a 400 Bad Request and a response highlighting the error.