ui/input: change Events to return all events at once

Single stepping events only makes sense for widgets with complex
state, e.g. the text.Editor. For the input.Events source, returning
all events in a single Events call is sufficient and more natural
for clients.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

ui/input/input.go

@@ -7,7 +7,7 @@ package input
 // Events maps an event handler key to the events
 // available to the handler.
 type Events interface {
-	Next(k Key) (Event, bool)
+	Events(k Key) []Event
 }
 
 // Key is the stable identifier for an event handler. For a handler h, the