chore(docs): typos

apps/docs/content/docs/customization/dark-mode.mdx

@@ -251,7 +251,7 @@ export const ThemeSwitcher = () => {
 };
 ```
 
-> **Note**: You can use any theme name you want, but make sure it exits in your
+> **Note**: You can use any theme name you want, but make sure it exists in your
 `tailwind.config.js` file. See [Create Theme](/docs/customization/create-theme) for more details.