Add Ctrl-U for clearing line to be standard w/ other editors

main.go

@@ -188,6 +188,13 @@ func initKeybindings() error {
 		}); err != nil {
 		return err
 	}
+	if err := g.SetKeybinding("", gocui.KeyCtrlU, gocui.ModNone,
+		func(g *gocui.Gui, v *gocui.View) error {
+			clearView("Input")
+			return nil
+		}); err != nil {
+		return err
+	}
 	if err := g.SetKeybinding("", gocui.KeyCtrlZ, gocui.ModNone,
 		func(g *gocui.Gui, v *gocui.View) error {
 			cmdJoin([]string{"/join", lastChat})