📄 Documentation for withResolvers()

withResolvers() is a very handy API that is part of the vanilla JS
stack and also part of v4. This adds jsdocs to the with resolvers and
also adds an entry in the async rosetta stone.

www/docs/async-rosetta-stone.mdx

@@ -201,6 +201,39 @@ function* main() {
 };
 ```
 
+## `Promise.withResolvers()` \<=> `withResolvers()`
+
+Both `Promise` and `Operation` can be constructed ahead of time without needing to begin the process that will resolve it. To do this with
+a `Promise`, use the `Promise.withResolvers()` function:
+
+```ts
+async function main() {
+  let { promise, resolve } = Promise.withResolvers();
+
+  setTimeout(resolve, 1000);
+
+  await promise;
+
+  console.log("done!")
+}
+```
+
+In effection:
+
+```ts
+import { withResolvers } from "effection";
+
+function* main() {
+  let { operation, resolve } = withResolvers();
+
+  setTimeout(resolve, 1000);
+
+  yield* operation;
+
+  console.log("done!");
+};
+```
+
 ## `for await` \<=> `for yield* each`
 
 Loop over an AsyncIterable with `for await`: