Fix typo: Pyssize_t => Py_ssize_t (GH-15411)

Author: sir-sigurd

Doc/data/refcounts.dat

@@ -2462,7 +2462,7 @@ PyUnicode_FromWideChar:Py_ssize_t:size::
 PyUnicode_AsWideChar:Py_ssize_t:::
 PyUnicode_AsWideChar:PyObject*:*unicode:0:
 PyUnicode_AsWideChar:wchar_t*:w::
-PyUnicode_AsWideChar:Pyssize_t:size::
+PyUnicode_AsWideChar:Py_ssize_t:size::
 
 PyUnicode_AsWideCharString:wchar_t*:::
 PyUnicode_AsWideCharString:PyObject*:unicode:0: