npx.md: give alternative to --node-arg since it was removed (#7111)

docs/lib/content/commands/npx.md

@@ -145,7 +145,8 @@ This resulted in some shifts in its functionality:
   always present in the executed process `PATH`.
 - The `--npm` option is removed.  `npx` will always use the `npm` it ships
   with.
-- The `--node-arg` and `-n` options are removed.
+- The `--node-arg` and `-n` options have been removed. Use [`NODE_OPTIONS`](https://nodejs.org/api/cli.html#node_optionsoptions) instead: e.g., 
+ `NODE_OPTIONS="--trace-warnings --trace-exit" npx foo --random=true`
 - The `--always-spawn` option is redundant, and thus removed.
 - The `--shell` option is replaced with `--script-shell`, but maintained
   in the `npx` executable for backwards compatibility.