[3.13] Normalize cdecl formatting as found elsewhere on ctypes.rst (GH-121379) (#124056)

Normalize cdecl formatting as found elsewhere on ctypes.rst (GH-121379)
(cherry picked from commit bbb36c0934b7644a9f8b67d3cae78aa6240e005a)

Co-authored-by: utkonos <utkonos@users.noreply.github.com>