GH-131296: fix clang-cl warning on Windows in overlapped.c

[chris-eibl]

I think this is a skip news?

• Issue: clang-cl issues many warnings when building on Windows #131296

[chris-eibl]

Fix warning : unused variable 'Overlapped_WSARecvFrom_doc' [-Wunused-const-variable].

Must be a left-over (and the only PyDoc_STRVAR in overlapped.c).

The currently used PyDoc_STRVAR is here:

cpython/Modules/clinic/overlapped.c.h

Lines 1145 to 1149 in 18249d9

	PyDoc_STRVAR(_overlapped_Overlapped_WSARecvFrom__doc__,
	"WSARecvFrom($self, handle, size, flags=0, /)\n"
	"--\n"
	"\n"
	"Start overlapped receive.");