Update post to highlight specific lines of code

Format can be found here:

Show line number:
https://github.com/timlrx/rehype-prism-plus#sample-markdown-to-html-output

Show diff lines:
timlrx/rehype-prism-plus#53

content/posts/20220901-post-with-code.mdx

@@ -10,12 +10,12 @@ type: Post
 
 Some other posts! with `some inline code`!
 
-```js
+```js showLineNumbers
 const a = 1;
 a = 2;
 ```
 
-```tsx
+```tsx showLineNumbers {5,15-17}
 import "@/styles/globals.css";
 
 import type { AppProps } from "next/app";
@@ -40,6 +40,13 @@ function MyApp({ Component, pageProps }: AppProps) {
 export default MyApp;
 ```
 
+```diff-js showLineNumbers {3-4}
+const a = 1;
+- a = 2;
++ a = 2;
+a = 3;
+```
+
 ```shell
 $ echo "Hello world!"
 ```