Fix image reference in custom modes documentation

Author: hannesrudolph

docs/features/custom-modes.md

@@ -151,7 +151,7 @@ You can find this setting within the prompt settings by clicking the <Codicon na
 2.  **Create New Mode:** Click the <Codicon name="add" /> button to the right of the Modes heading
 3.  **Fill in Fields:**
 
-        <img src="/img/custom-modes/custom-modes-3.png" alt="Custom mode creation interface in the Prompts tab" width="600" />
+        <img src="/img/custom-modes/custom-modes-2.png" alt="Custom mode creation interface in the Prompts tab" width="600" />
         *The custom mode creation interface showing fields for name, slug, save location, role definition, available tools, and custom instructions.*
 
     * **Name:** Enter a display name for the mode