Clear keybinding functions in resetHelpersAndControllers

When switching to a repo that was open before, the context tree is reused, so
before adding keybinding functions to those contexts again, we need to clear the
old ones.

pkg/gui/types/context.go

@@ -74,6 +74,7 @@ type IBaseContext interface {
 
 	AddKeybindingsFn(KeybindingsFn)
 	AddMouseKeybindingsFn(MouseKeybindingsFn)
+	ClearAllBindingsFn()
 
 	// This is a bit of a hack at the moment: we currently only set an onclick function so that
 	// our list controller can come along and wrap it in a list-specific click handler.