Add Bun section to Getting started

Closes GH-2517.

Reviewed-by: Remco Haszing <remcohaszing@gmail.com>
Reviewed-by: Christian Murphy <christian.murphy.42@gmail.com>
Reviewed-by: Titus Wormer <tituswormer@gmail.com>

Author: karlhorky

docs/docs/getting-started.mdx

@@ -62,7 +62,7 @@ MDX is a language that’s compiled to JavaScript.
 The easiest way to get started is to use an integration for your bundler if you
 have one:
 
-* if you use **esbuild**,
+* if you use **esbuild** (or Bun),
   install and configure [`@mdx-js/esbuild`][mdx-esbuild]
 * if you use **Rollup** (or Vite),
   install and configure [`@mdx-js/rollup`][mdx-rollup]
@@ -234,6 +234,10 @@ etc.) you use.
 To use more modern JavaScript features than what your users support,
 [configure esbuild’s `target`][esbuild-target].
 
+See also [¶ Bun][javascript-engines-bun],
+which you might be using,
+for more info.
+
 #### Rollup
 
 <details>
@@ -798,6 +802,26 @@ MDX files can be imported in Node by using
 [`@mdx-js/node-loader`][mdx-node-loader].
 See its readme on how to configure it.
 
+#### Bun
+
+MDX files can be imported in [Bun][] by using
+[`@mdx-js/esbuild`][mdx-esbuild].
+
+<details>
+  <summary>Expand example</summary>
+
+  ```toml path="bunfig.toml"
+  preload = ["./bun-mdx.ts"]
+  ```
+
+  ```js twoslash path="bun-mdx.ts"
+  import {plugin} from 'bun'
+  import mdx from '@mdx-js/esbuild'
+
+  plugin(mdx())
+  ```
+</details>
+
 ## Further reading
 
 * If you want to use MDX content in your project,
@@ -911,6 +935,10 @@ See its readme on how to configure it.
 
 [build-system-vite]: #vite
 
+[bun]: https://bun.sh
+
+[javascript-engines-bun]: #bun
+
 [bundler-esbuild]: #esbuild
 
 [bundler-rollup]: #rollup