chore: update docs to point to webExt instead of runner; update config in demo (#1582)

docs/guide/essentials/config/browser-startup.md

@@ -22,7 +22,7 @@ You can configure browser startup in 3 places:
    });
    ```
 
-2. `<rootDir>/wxt.config.ts`: Via the [`runner` config](/api/reference/wxt/interfaces/InlineConfig#runner), included in version control
+2. `<rootDir>/wxt.config.ts`: Via the [`webExt` config](/api/reference/wxt/interfaces/InlineConfig#webext), included in version control
 3. `$HOME/web-ext.config.ts`: Provide default values for all WXT projects on your computer
 
 ## Recipes

packages/wxt-demo/wxt.config.ts

@@ -20,7 +20,7 @@ export default defineConfig({
   analysis: {
     open: true,
   },
-  runner: {
+  webExt: {
     startUrls: ['https://duckduckgo.com'],
   },
   example: {