chore: improve inspector docs (#1197)

* chore: improve inspector docs

* Update packages/vite-plugin-svelte-inspector/README.md

Co-authored-by: Rich Harris <[email protected]>

---------

Co-authored-by: Rich Harris <[email protected]>

Author: dominikg

.changeset/angry-dolls-cut.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/vite-plugin-svelte-inspector': patch
+---
+
+docs: update usage instructions in readme and link to docs

packages/vite-plugin-svelte-inspector/README.md

@@ -4,23 +4,23 @@ A [Svelte](https://svelte.dev) inspector plugin for [Vite](https://vitejs.dev).
 
 ## Usage
 
+This plugin is automatically installed as a dependency of [@sveltejs/vite-plugin-svelte](https://www.npmjs.com/package/@sveltejs/vite-plugin-svelte).
+
+You can enable it in `svelte.config.js` by adding the `vitePlugin.inspector` option.
+
 ```js
-// vite.config.js
-import { defineConfig } from 'vite';
-import { svelte } from '@sveltejs/vite-plugin-svelte';
-import { svelteInspector } from '@sveltejs/vite-plugin-svelte-inspector';
-
-export default defineConfig({
-  plugins: [
-    // the svelte plugin is required to work
-    svelte(),
-    svelteInspector({
-      /* plugin options */
-    })
-  ]
-});
+// svelte.config.js
+export default {
+  vitePlugin: {
+    inspector: true
+  }
+};
 ```
 
+Now simply press `alt-x` (`option-x` on MacOS) on a page served by the Vite dev server to activate inspect mode. Click on a highlighted element to jump to its source code in your editor.
+
+Also check out the [docs](https://github.com/sveltejs/vite-plugin-svelte/blob/main/docs/inspector.md) for customization options.
+
 ## License
 
 [MIT](./LICENSE)