Revert "add close command at global level"

This reverts commit f0a0c5aa73.

commands/terminal/close.go

@@ -0,0 +1,30 @@
+package terminal
+
+import (
+	"errors"
+
+	"git.sr.ht/~sircmpwn/aerc/widgets"
+)
+
+type Close struct{}
+
+func init() {
+	register(Close{})
+}
+
+func (_ Close) Aliases() []string {
+	return []string{"close"}
+}
+
+func (_ Close) Complete(aerc *widgets.Aerc, args []string) []string {
+	return nil
+}
+
+func (_ Close) Execute(aerc *widgets.Aerc, args []string) error {
+	if len(args) != 1 {
+		return errors.New("Usage: close")
+	}
+	term, _ := aerc.SelectedTab().(*widgets.Terminal)
+	term.Close(nil)
+	return nil
+}