More constructors for ChangeableText

src/textinterface.h

@@ -30,6 +30,10 @@ public:
 class ChangeableText : public virtual TextInterface
 {
 public:
+    ChangeableText() = default;
+    ChangeableText(std::string &&title) : m_title{std::move(title)} {}
+    ChangeableText(const std::string &title) : m_title{title} {}
+
     std::string text() const override { return m_title; }
     void setTitle(std::string &&title) { m_title = std::move(title); }
     void setTitle(const std::string &title) { m_title = title; }