[fix] search box: clear button don't appear on mouse-copy

You have to copy and paste the query without using the keyboard to replicate the
issue. As soon as you press the keyboard the cross appears. [1]

- [1] https://github.com/searxng/searxng/issues/3725#issuecomment-2282655272

Reported-by: @Immortality-IMT in [1]
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/static/themes/simple/src/js/main/search.js

@@ -32,7 +32,7 @@
       updateClearButton();
       ev.preventDefault();
     });
-    qinput.addEventListener('keyup', updateClearButton, false);
+    qinput.addEventListener('input', updateClearButton, false);
   }
 
   searxng.ready(function () {