As per my understanding there is no such parameter to limit the suggestions but this could go as a feature request if this has a valid use case.
Can you put some light on the use case, as in why it is required to limit the suggestions, because the idea of enabling suggestion is to show user matching records as they type to avoid keying in complete text, so limiting the suggestions seems like defeating the purpose.
If you have a valid use case, you can reach out to GCS and they can help to place a feature request.
Its not possible to limit the number of suggestions.
The valid scenario is to limit the suggestions list so that we can control it.
For example, if the list of suggestions is pretty big, then we would want to restrict it, say 15 suggestions, at once.
The default limit of suggestions list is 10.
And from UI it can't be changed, you can modify it for api calls.