fix: Update placeholder text and error message (#6263)

This commit improves the clarity of the llama.cpp extension.

- Corrected a placeholder example from `GGML_VK_VISIBLE_DEVICES='0,1'` to `GGML_VK_VISIBLE_DEVICES=0,1` for better accuracy.
- Changed an ambiguous error message from `"Failed to load llama-server: ${error}"` to the more specific `"Failed to load llamacpp backend"`.

extensions/llamacpp-extension/settings.json

@@ -17,7 +17,7 @@
     "controllerType": "input",
     "controllerProps": {
       "value": "none",
-      "placeholder": "Eg, GGML_VK_VISIBLE_DEVICES='0,1'",
+      "placeholder": "Eg. GGML_VK_VISIBLE_DEVICES=0,1",
       "type": "text",
       "textAlign": "right"
     }

extensions/llamacpp-extension/src/index.ts

@@ -1763,7 +1763,7 @@ export default class llamacpp_extension extends AIEngine {
       return dList
     } catch (error) {
       logger.error('Failed to query devices:\n', error)
-      throw new Error(`Failed to load llama-server: ${error}`)
+      throw new Error("Failed to load llamacpp backend")
     }
   }