content(resources): clean up markdown files, headings & codeblocks

src/content/resources/javascript/promises/intro.md

@@ -16,7 +16,7 @@ completed at a later time. Much like in real life, when you create a promise, yo
 to fulfill that promise. However, sometimes things go wrong where you can no longer fulfill
 a promise you made. This is essentially the main idea behind how promises work in javascript.
 
-### Basics
+## Basics
 
 When you create a Promise or call a function that returns a Promise in Javascript, you're left
 with an object that can either resolve into the actual value that you were promised, or it
@@ -24,7 +24,7 @@ can reject and leave you with an error for why that promise failed.
 
 We can access these values using the `.then` and `.catch` methods on the `Promise` object respectively.
 
-### A Simple Example
+## A Simple Example
 
 First, let's explore a bit of a made-up example. Imagine we have a promise-returning function
 called `getMembers` that retrieves all the members in a discord server. When we execute this
@@ -50,7 +50,7 @@ getMembers("The Programmers Hangout").then(members => {
 
 This way we are able to make sure that we only try to `console.log` when the `getMembers` function has resolved and ready to be used.
 
-### Beginner Mistakes
+## Beginner Mistakes
 
 Promises are possibly the #1 most common source of confusion for beginners. In order
 to avoid falling in pitfalls yourself, you have to remember 2 things about Javascript when
@@ -85,7 +85,7 @@ getWeather("Los Angeles").then(weather => {
 });
 ```
 
-### Real World Example
+## Real World Example
 
 Here is a real function that gets character information from the Rick and Morty API.
 You can try it in your browser if you want to test it out.

src/content/resources/javascript/spread-operator.md

@@ -12,8 +12,6 @@ external_resources:
     href: "https://www.freecodecamp.org/news/spread-operator-and-rest-parameter-in-javascript-es6-4416a9f47e5e/"
 ---
 
-# An overview of the spread operator
-
 Spread operator (or spread syntax) is a powerful feature in Javascript which allows you to do such things as merging or copying objects, expanding an array into function arguments and a lot more. In this post, we are going to cover most of its use-cases.
 
 ## Copying an object

src/content/resources/javascript/variables.md

@@ -5,8 +5,6 @@ created_at: "2019/10/06"
 title: Variables
 ---
 
-## Variables
-
 A `variable` in Javascript is a "named container" that can hold data. Variables are declared by giving them a name and a value - the `name` allows you to reference the variable throughout your program, and the `value` is the current value the variable represents.
 
 Variables can be defined in the following ways:
@@ -117,15 +115,15 @@ console.log(myVar); // 'test'
 This is fixed using `let`
 
 ```js
-for(let i = 0; i < 5; i++) {
+for (let i = 0; i < 5; i++) {
   console.log(i);
 }
 console.log(i); // Error: i is undefined
 
 if (true) {
-  let myVar = 'test';
+  let myVar = "test";
 }
-console.log(myVar) // Error: myVar is undefined
+console.log(myVar); // Error: myVar is undefined
 ```
 
 However, if the above code was in a function, this would not be the case. In the case of a function, the variable will be scoped to the given function, and not accessible outside it. Eg: