S2HDMIV: fix PDG scheme numbering
Fixing the numbering scheme as follows:
-
h2is the heavy neutral Higgs in this 2HDM variant model, H_2^0:29->35 -
Ahis the pseudo-scalar Higgs, A_0:38->36 -
~Xiis a pseudo-scalar Dark Matter particle, \chi (actual label in the paper):30->51
~Xi has zero width, so the related PDGid change only shows up once in parameters.py (for the mass block).