chore: fix external definition and new device support issue template render

.github/ISSUE_TEMPLATE/external_converter.yaml

@@ -36,6 +36,7 @@ body:
       attributes:
           label: External converter
           description: Code of the external converter, to retrieve in the Z2M frontend go to Settings -> Dev Console -> External Converters
+          render: JavaScript
       validations:
           required: true
     - type: textarea

.github/ISSUE_TEMPLATE/new_device_support.yaml

@@ -40,7 +40,7 @@ body:
       attributes:
           label: External definition
           description: See [Creating the external definition](https://www.zigbee2mqtt.io/advanced/support-new-devices/01_support_new_devices.html#_2-creating-the-external-definition)
-          render: shell
+          render: JavaScript
       validations:
           required: true
     - type: textarea