docs: Documentation fix for LibreNMS provider (#5345)

Author: bsteinert

keep/providers/libre_nms_provider/libre_nms_provider.py

@@ -53,10 +53,11 @@ class LibreNmsProvider(BaseProvider):
 2. Create transport with type API and POST method
 3. Give a Transport Name and select Transport Type as API
 4. Select the API Method as POST
-3. Enter the Keep webhook URL: {keep_webhook_api_url}
-4. Add header "X-API-KEY" with your Keep API key (webhook role)
-5. For JSON body format, refer to [Keep documentation](https://docs.keephq.dev/providers/documentation/libre_nms-provider)
-6. Save the transport
+3. Enter first part (without the options) of the Keep webhook URL as API URL: {keep_webhook_api_url} (until the "?")
+4. Remove the questionmark and put the remaining string starting with "provider_id=" under Options
+5. Add header "X-API-KEY" with your Keep API key (webhook role)
+6. For JSON body format, refer to [Keep documentation](https://docs.keephq.dev/providers/documentation/libre_nms-provider)
+7. Save the transport
     """
 
     PROVIDER_DISPLAY_NAME = "LibreNMS"