doc: amplify warning for execute callback

Add specific recommendation not to use the
to the napi-env parameter in napi_async_execute_callback

PR-URL: nodejs#28738
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

doc/api/n-api.md

@@ -463,6 +463,8 @@ Implementations of this type of function should avoid making any N-API calls
 that could result in the execution of JavaScript or interaction with
 JavaScript objects. Most often, any code that needs to make N-API
 calls should be made in `napi_async_complete_callback` instead.
+Avoid using the `napi_env` parameter in the execute callback as
+it will likely execute JavaScript.
 
 #### napi_async_complete_callback
 <!-- YAML
@@ -4028,6 +4030,8 @@ The `execute` function should avoid making any N-API calls
 that could result in the execution of JavaScript or interaction with
 JavaScript objects. Most often, any code that needs to make N-API
 calls should be made in `complete` callback instead.
+Avoid using the `napi_env` parameter in the execute callback as
+it will likely execute JavaScript.
 
 These functions implement the following interfaces: