pidl: avoid py compile issues with --pidl-developer

pidl: avoid py compile issues with --pidl-developer

We get these warnings-as-errors:

librpc/gen_ndr/py_netlogon.c:61903:53: error: stray ‘\’ in program
61903 |    PyErr_Format(PyExc_TypeError, "Expected type %s",\  //<PIDL> Parse::Pidl::Samba4::Python::ConvertObjectFromPythonData  lib/Parse/Pidl/Samba4/Python.pm:2005

but the '\' is unnecessary and unconventional anyway, since we're in a
function argument list.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Autobuild-User(master): Andrew Bartlett <abartlet@samba.org>
Autobuild-Date(master): Fri Feb  3 03:27:54 UTC 2023 on atb-devel-224