It is not normal to put a traveller over the
companionway. It would interfere with the later placement of a
dodger (unless it was very high) and it could be dangerous (beheading) to anyone exposed during an accidental gybe. Without knowing more about your boat, I couldn't guess where the best place to put it might be, but somewhere the end of the boom is normal just because it gives the best
purchase and control.
If the end of your boom happens to fall over the companionway
hatch however, then you should consider moving the traveller to a position in front (forward) of your
hatch. It won't interfere with anything there and, will be safer.
Good luck
Joe S