on-char in editor<%>

Handles keyboard input to the editor.

Consider overriding on-local-char or on-default-char instead of this method.

• (send an-editor on-char event) -> void
     event : key-event% object

  Either passes this event on to a caret-owning snip or calls on-local-char. In the latter case, text% first calls hide-cursor-until-moved.