Support uncurried mode

[TheSpyder]

The biggest issue I had with uncurried was a compiler bug: rescript-lang/rescript#6517. This hasn't been released yet but I've confirmed it with a local compiler build.

However there is a limitation that doesn't seem like it can be fixed: rescript-lang/rescript#6531

The solution is just to offer multi-arg function types in the Event module.

rescript-nodejs/src/Event.res

Lines 24 to 25 in 83e9eba

	external fromString: string => t<'a => 'b, 'ty> = "%identity"
	external fromSymbol: Js.Types.symbol => t<'a => 'b, 'ty> = "%identity"