#10124: typo fix.

Doc/howto/cporting.rst

@@ -50,7 +50,7 @@ Python 3.0's :func:`str` (``PyString_*`` functions in C) type is equivalent to
 compatibility with 3.0, :c:type:`PyUnicode` should be used for textual data and
 :c:type:`PyBytes` for binary data.  It's also important to remember that
 :c:type:`PyBytes` and :c:type:`PyUnicode` in 3.0 are not interchangeable like
-:c:type:`PyString` and :c:type:`PyString` are in 2.x.  The following example
+:c:type:`PyString` and :c:type:`PyUnicode` are in 2.x.  The following example
 shows best practices with regards to :c:type:`PyUnicode`, :c:type:`PyString`,
 and :c:type:`PyBytes`. ::