consider making / same priority as *

[ldemailly]

in go x * 4 / 9 is (x*4)/9 while current grol (because of divide priority) it’s * 0 without ()

let’s remember why though before changing it
and double check go too

[ldemailly]

ah, found #230 : compact expression 1./(a*b) turns into 1./a*b but maybe the priority for compact vs for eval doesn't have to be the same