docs: update Node.js version requirements for 11.x (#5329)

Author: JoshuaKGoldberg

docs-next/src/content/docs/getting-started.mdx

@@ -12,7 +12,7 @@ First, install the [`mocha` package](https://www.npmjs.com/package/mocha) as a d
 <PackageManagers dev type="add" pkg="mocha" />
 
 :::note
-As of v10.0.0, Mocha requires [Node.js](https://nodejs.org) v14.0.0 or newer.
+As of v11.0.0, Mocha requires [Node.js](https://nodejs.org) `^18.18.0 || ^20.9.0 || >=21.1.0`.
 :::
 
 ## 2. Test File

docs/index.md

@@ -65,7 +65,7 @@ or as a development dependency for your project:
 $ npm install --save-dev mocha
 ```
 
-> As of v10.0.0, Mocha requires Node.js v14.0.0 or newer.
+> As of v11.0.0, Mocha requires [Node.js](https://nodejs.org) `^18.18.0 || ^20.9.0 || >=21.1.0`.
 
 ## Getting Started