String2, Array2, Promise2 -> Core (#771)

Author: cknitt

pages/docs/manual/latest/array-and-list.mdx

@@ -25,8 +25,6 @@ ReScript arrays' items must have the same type, i.e. homogeneous.
 
 ### Usage
 
-See the [Js.Array](api/js/array) API.
-
 Access & update an array item like so:
 
 <CodeTab labels={["ReScript", "JS Output"]}>
@@ -38,7 +36,7 @@ let firstItem = myArray[0] // "hello"
 
 myArray[0] = "hey" // now ["hey", "world", "how are you"]
 
-let pushedValue = Js.Array2.push(myArray, "bye")
+myArray->Array.push("bye")
 ```
 ```js
 var myArray = ["hello", "world", "how are you"];

pages/docs/manual/latest/async-await.mdx

@@ -180,7 +180,7 @@ This can be done by wrapping your `await` calls in a new `{}` closure.
 @val external fetchUserMail: string => promise<string> = "GlobalAPI.fetchUserMail"
 
 let fetchData = async () => {
-  let mail = {await fetchUserMail("1234")}->Js.String2.toUpperCase
+  let mail = {await fetchUserMail("1234")}->String.toUpperCase
   Console.log(`All upper-cased mail: ${mail}`)
 }
 ```
@@ -242,13 +242,13 @@ async function fetchData(param) {
 
 ## `await` multiple promises
 
-We can utilize the `Js.Promise2` module to handle multiple promises. E.g. let's use `Js.Promise2.all` to wait for multiple promises before continuing the program:
+We can utilize the `Promise` module to handle multiple promises. E.g. let's use `Promise.all` to wait for multiple promises before continuing the program:
 
 ```res
 let pauseReturn = (value, timeout) => {
-  Js.Promise2.make((~resolve, ~reject) => {
+  Promise.make((resolve, _reject) => {
     Js.Global.setTimeout(() => {
-      resolve(. value)
+      resolve(value)
     }, timeout)->ignore
   })
 }
@@ -258,7 +258,7 @@ let logMultipleValues = async () => {
   let promise2 = pauseReturn("value2", 1200)
   let promise3 = pauseReturn("value3", 500)
 
-  let all = await Js.Promise2.all([promise1, promise2, promise3])
+  let all = await Promise.all([promise1, promise2, promise3])
 
   switch all {
   | [v1, v2, v3] => Console.log(`All values: ${v1}, ${v2}, ${v3}`)

pages/docs/manual/latest/promise.mdx

@@ -93,7 +93,7 @@ external fetchMessage: string => promise<string> = "global.fetchMessage"
 let logAsyncMessage = async () => {
   let messages = await Js.Promise2.all([fetchMessage("message1"), fetchMessage("message2")])
 
-  Console.log(Js.Array2.joinWith(messages, ", "))
+  Console.log(messages->Array.joinWith(", "))
 }
 ```