Doc: c-api: fix order of PyMemberDef fields (pythonGH-112879)

(cherry picked from commit 42a86df)

Co-authored-by: Inada Naoki <songofacandy@gmail.com>

Doc/c-api/structures.rst

@@ -419,15 +419,15 @@ Accessing attributes of extension types
 
          The string should be static, no copy is made of it.
 
-   .. c:member:: Py_ssize_t offset
-
-      The offset in bytes that the member is located on the type’s object struct.
-
    .. c:member:: int type
 
       The type of the member in the C struct.
       See :ref:`PyMemberDef-types` for the possible values.
 
+   .. c:member:: Py_ssize_t offset
+
+      The offset in bytes that the member is located on the type’s object struct.
+
    .. c:member:: int flags
 
       Zero or more of the :ref:`PyMemberDef-flags`, combined using bitwise OR.