Update index.mdx (#1822)

Author: Jacob Lamb

src/pages/blog/tailwindcss-v4-alpha/index.mdx

@@ -270,7 +270,7 @@ $ npm install tailwindcss@next @tailwindcss/vite@next
 
 Then add our plugin to your `vite.config.ts` file:
 
-```ts {{ filename: 'vite-config.ts' }}
+```ts {{ filename: 'vite.config.ts' }}
 import tailwindcss from '@tailwindcss/vite'
 import { defineConfig } from 'vite'