Gui: avoid code duplication in PythonEditor

src/Gui/PythonEditor.cpp

@@ -238,25 +238,7 @@ void PythonEditor::keyPressEvent(QKeyEvent* e)
 
 void PythonEditor::onComment()
 {
-    QTextCursor cursor = textCursor();
-    int selStart = cursor.selectionStart();
-    int selEnd = cursor.selectionEnd();
-    QTextBlock block;
-    cursor.beginEditBlock();
-    for (block = document()->begin(); block.isValid(); block = block.next()) {
-        int pos = block.position();
-        int off = block.length()-1;
-        // at least one char of the block is part of the selection
-        if ( pos >= selStart || pos+off >= selStart) {
-            if ( pos+1 > selEnd )
-                break; // end of selection reached
-            cursor.setPosition(block.position());
-            cursor.insertText(QLatin1String("#"));
-                selEnd++;
-        }
-    }
-
-    cursor.endEditBlock();
+    prepend(QStringLiteral("#"));
 }
 
 void PythonEditor::onUncomment()