How would you even determine that? You can't ask the dead ones if they would have not committed suicide if their pronouns had been used, and the ones that don't commit suicide will probably attribute it to whatever you tell them.

They commit suicide because the weight of reality crushes the fantasy of what their life is. So obviously anything that eases that conflict will lower suicide rates, but it isn't the responsibility of reality to change to suit fantasy. If we want to lower suicide rates, they need to conform their fantasy to reality.