io/pointer: remove Foremost priority

The only known use-case (nested scrolling) now works without special
treatment of the foremost handler.

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

io/pointer/pointer.go

@@ -207,9 +207,6 @@ const (
 	// Shared priority is for handlers that
 	// are part of a matching set larger than 1.
 	Shared Priority = iota
-	// Foremost priority is like Shared, but the
-	// handler is the foremost of the matching set.
-	Foremost
 	// Grabbed is used for matching sets of size 1.
 	Grabbed
 )
@@ -295,8 +292,6 @@ func (p Priority) String() string {
 	switch p {
 	case Shared:
 		return "Shared"
-	case Foremost:
-		return "Foremost"
 	case Grabbed:
 		return "Grabbed"
 	default: