Install guide: Throw whole plugin config in one line (#2)

* Update install.mdx

* Format with prettier

---------

Co-authored-by: Reuben Tier <[email protected]>

apps/docs/src/content/docs/guides/install.mdx

@@ -3,29 +3,29 @@ title: Install Theme
 description: Install the template theme for Starlight.
 ---
 
-import { Steps } from '@astrojs/starlight/components';
-import { PackageManagers } from 'starlight-package-managers'
+import { Steps } from "@astrojs/starlight/components";
+import { PackageManagers } from "starlight-package-managers";
 
 <Steps>
 
 1. Install the theme package to your project with your preferred package manager:
-   <PackageManagers pkg="starlight-theme-template"/>
+
+   <PackageManagers pkg="starlight-theme-template" />
 
 2. Add the theme to your Starlight config.
-   ```ts title="astro.config.mjs" ins={1,9}
+
+   ```ts title="astro.config.mjs" ins={1,8}
    import theme from "starlight-theme-template";
 
    export default defineConfig({
-     // ...
-     integrations: [
-       starlight({
-         // ...
-         plugins: [
-           theme()
-         ]
-       })
-     ]
-   })
+   	// ...
+   	integrations: [
+   		starlight({
+   			// ...
+   			plugins: [theme()],
+   		}),
+   	],
+   });
    ```
 
 </Steps>