pythongh-141650: Fix typo in xml.sax.saxutils.unescape documentation (python#141652)

Author: TamzinHadasa

Doc/library/xml.sax.utils.rst

@@ -37,7 +37,7 @@ or as base classes.
 
    You can unescape other strings of data by passing a dictionary as the optional
    *entities* parameter.  The keys and values must all be strings; each key will be
-   replaced with its corresponding value.  ``'&amp'``, ``'<'``, and ``'>'``
+   replaced with its corresponding value.  ``'&'``, ``'<'``, and ``'>'``
    are always unescaped, even if *entities* is provided.