Semanticize intermediate headings

blog_posts/async-javascript-cheatsheet.md

@@ -7,13 +7,13 @@ cover: blog_images/green-plant.jpg
 excerpt: Learn everything you need to know about promises and asynchronous JavaScript with this handy cheatsheet.
 ---
 
-**Promise basics**
+### Promise basics
 
 - **Promises** start in a **pending state**, neither fullfiled or rejected.
 - When the operation is completed, a promise will become **fullfiled with a value**.
 - If the operation fails, a promise will get **rejected with an error**.
 
-**Creating promises**
+### Creating promises
 
 - The function passed to a `new Promise` will execute synchronously.
 - Use `resolve()` or `reject()` to create promises from values.
@@ -34,7 +34,7 @@ new Promise((resolve, reject) => {
 const delay = (ms) => new Promise(resolve => setTimeout(resolve, ms));
 ```
 
-**Handling promises**
+### Handling promises
 
 - `Promise.prototype.then()` accepts two optional arguments (`onFulfilled`, `onRejected`).
 - `Promise.prototype.then()` will call `onFulfilled` once the promise is fulfilled.
@@ -68,7 +68,7 @@ promisedOperation()
 
 - All three of the above methods will not be executed at least until the next tick, even for promises that already have an outcome.
 
-**Combining promises**
+### Combining promises
 
 - `Promise.all()` turns an array of promises into a promise of an array.
 - If any promise is rejected, the error will pass through.
@@ -89,7 +89,7 @@ Promise
   });
 ```
 
-**async/await**
+### async/await
 
 - Calling an `async` function always results in a promise.
 - `(async () => value)()` will resolve to `value`.