Doc: fix example code

* remove unused import
* add missing import

Author: Hanaasagi

docs/pages/asking_for_input.rst

@@ -781,7 +781,7 @@ attribute. We can change the key bindings by changing this attribute from
 
     from prompt_toolkit import prompt
     from prompt_toolkit.application.current import get_app
-    from prompt_toolkit.filters import Condition
+    from prompt_toolkit.enums import EditingMode
     from prompt_toolkit.key_binding import KeyBindings
 
     def run():