Merged patch from https://lists.sr.ht/~rjarry/aerc-devel/patches/34390

Reference: https://lists.sr.ht/~rjarry/aerc-devel/patches/34390

commands/compose/markup.go

@@ -0,0 +1,36 @@
+package compose
+
+import (
+	"fmt"
+	"git.sr.ht/~rjarry/aerc/widgets"
+)
+
+type MarkUp struct{}
+
+func init() {
+	register(MarkUp{})
+}
+
+func (MarkUp) Aliases() []string {
+	return []string{"markup"}
+}
+
+func (MarkUp) Complete(aerc *widgets.Aerc, args []string) []string {
+	composer, _ := aerc.SelectedTabContent().(*widgets.Composer)
+	return composer.GetMarkups()
+}
+
+func (MarkUp) Execute(aerc *widgets.Aerc, args []string) error {
+	if len(args) != 2 {
+		return fmt.Errorf("Usage: :markup <label>")
+	}
+	markupKey := args[1]
+	composer, _ := aerc.SelectedTabContent().(*widgets.Composer)
+	if err := composer.GenerateMarkup(markupKey); err != nil {
+		aerc.PushError(err.Error())
+		return err
+	} else {
+		aerc.PushSuccess(fmt.Sprintf("Markup generated"))
+	}
+	return nil
+}