Leave block selection mode

The patch makes the editor leave block selection
mode when users continue to select text with
the keyboard. The editor will smoothly convert
to standard selection mode.

src/plugins/texteditor/basetexteditor.cpp

@@ -1314,6 +1314,13 @@ void BaseTextEditor::keyPressEvent(QKeyEvent *e)
             handleBlockSelection(diff_row, diff_col);
             e->accept();
             return;
+        } else {
+            // leave block selection mode
+            if (d->m_inBlockSelectionMode) {
+                d->m_inBlockSelectionMode = false;
+                d->m_blockSelection.clear();
+                viewport()->update();
+            }
         }
 #endif
         break;