Suggest pickers (user, group, page, etc.) should indicate if there are more results than the ones displayed

The current behavior is this:

• when you focus the picker it shows a list of default suggestions / results; some users think that those are the only options available and that the text input is useful only to filter the listed results;
• when you type you get a limited list of suggestions; it's not clear if those are the only suggestions found or if those are just the top N results (unless the results are less than the limit)

So it might help to:

• let the users know that we're showing top N results out of T (total); this could be a message displayed somewhere inside the list of suggestions, maybe at the end
• let the users know that they should type to get more suggestions; this could be a placeholder for the text input used to filter