core: button: do not warn on double press

If running on startup, this happens on every keypress with phoc.

src/core/button.rs

@@ -288,7 +288,6 @@ impl<D: Display, K: Keyboard> Button<D, K> {
     pub fn press(&mut self, id: usize, x: f64, y: f64)
     {
         if self.presses[id].is_some() {
-            eprintln!("warn: pressed same ID twice before releasing");
             return;
         }