Fix prethen value

lib/index.d.ts

@@ -13,7 +13,7 @@ interface CancelablePromise<T> extends Promise<T> {
 
 interface OrderPromise<C, T> extends CancelablePromise<T> {
   channel: C;
-  prethen(onFulfilled: (value: C) => void): void;
+  prethen(onFulfilled: (value: T) => void): void;
 }
 type UnwrapOrderPromise<A> = A extends OrderPromise<any, infer T> ? T : never 
 
@@ -45,7 +45,6 @@ export interface WriteChannel<T> {
 
 export type ReadWriteChannel<T> = ReadChannel<T> & WriteChannel<T>;
 
-
 import { Functionalify, Typify } from './functional';
 // Ideally these would not be channels of `any`, but I couldn't find a way to pass on the generic arguments
 type FunctionalInterface =