Fix collapsed block indicator

In combination with ifdef'ed-out blocks, the collapse block
indicator was sometimes painted with the ifdef'ed out color.

src/plugins/texteditor/basetexteditor.cpp

@@ -2182,6 +2182,7 @@ void BaseTextEditor::paintEvent(QPaintEvent *e)
             block = doc->findBlockByLineNumber(block.firstLineNumber());
         }
     }
+    painter.setPen(context.palette.text().color());
 
     if (backgroundVisible() && !block.isValid() && offset.y() <= er.bottom()
         && (centerOnScroll() || verticalScrollBar()->maximum() == verticalScrollBar()->minimum())) {