Desktop: create new custom TextEdit widget for notes-field

Currently, the notes field uses a QTextEdit, which doesn't
send a signal if it goes out of focus.  But for undo of
dive-editing we don't want to create an undo object for
*every* text change.

Thus, create a custom TextEdit widget that derives from
QTextEdit and turns the focusOutEvent into a editingFinished
signal.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

desktop-widgets/textedit.h

@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef TEXTEDIT_H
+#define TEXTEDIT_H
+
+#include <QTextEdit>
+
+// QTextEdit does not possess a signal that fires when the user finished
+// editing the text. This subclass therefore overrides the focusOutEvent
+// and sends the textEdited signal.
+class TextEdit : public QTextEdit {
+	Q_OBJECT
+public:
+	using QTextEdit::QTextEdit; // Make constructors of QTextEdit available
+signals:
+	void editingFinished();
+private:
+	void focusOutEvent(QFocusEvent *ev) override;
+};
+
+#endif