如何更改角度js中的{{}} thingys？至 [{ }]

I know there is some way to change the ng-binding thingys {{ expression }} to {[ expression ]} because I've done it before but I don't remember what the thingys are called.. so I don't know how to look it up. I can't find it in the angular docs.I know there is some way to change the ng-bindi