pythongh-93738: Documentation C syntax (:c:type:PyUnicodeObject* -> :c:expr:PyUnicodeObject*) (pythonGH-97783)

:c:type:`PyUnicodeObject*` -> :c:expr:`PyUnicodeObject*`
(cherry picked from commit 898834e)

Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>

Author: AA-Turner

Doc/c-api/unicode.rst

@@ -866,7 +866,7 @@ conversion function:
    ParseTuple converter: decode :class:`bytes` objects -- obtained either
    directly or indirectly through the :class:`os.PathLike` interface -- to
    :class:`str` using :c:func:`PyUnicode_DecodeFSDefaultAndSize`; :class:`str`
-   objects are output as-is. *result* must be a :c:type:`PyUnicodeObject*` which
+   objects are output as-is. *result* must be a :c:expr:`PyUnicodeObject*` which
    must be released when it is no longer used.
 
    .. versionadded:: 3.2