Merge pull request #3076 from surajnarwade/update-doc

update instruction for headless mode on mac

Author: k8s-ci-robot

docs/installation/desktop/headless.mdx

@@ -28,6 +28,11 @@ import TabItem from '@theme/TabItem';
     ```bash
     ./Headlamp --headless
     ```
+    
+    If you have installed using brew then,
+    ```bash
+    /Applications/Headlamp.app/Contents/MacOS/Headlamp --headless
+    ```
   </TabItem>
   <TabItem value="windows" label="Windows">
     ```powershell