curry

Implement curry(fn). It returns a function that collects arguments over one or more calls. It calls fn once it has enough arguments.

• "Enough" means at least fn.length arguments. fn.length is the number of parameters fn declares.
• Each call may pass any number of arguments: c(1)(2)(3), c(1, 2)(3) and c(1, 2, 3) all work.
• While there aren't enough arguments, return a new function that keeps collecting. Calling it with no arguments adds nothing.
• A partial result can be reused. For example, after const add10 = c(10), the calls add10(1)(2) and add10(5, 5) give two independent results.
• When enough arguments arrive, call fn with all of them and return its result.
• If fn.length is 0, the first call runs fn.