Cleanup: add missing break statements

The current code of course works just fine. But there's a risk someone might
add something to one of these cases and not realize that there is an implicit
fall through going on. This is cleaner.

Found by Coverity. Fixes CID 350079

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-models/weightmodel.cpp

@@ -63,12 +63,15 @@ QVariant WeightModel::data(const QModelIndex &index, int role) const
 	case Qt::DecorationRole:
 		if (index.column() == REMOVE)
 			return trashIcon();
+		break;
 	case Qt::SizeHintRole:
 		if (index.column() == REMOVE)
 			return trashIcon().size();
+		break;
 	case Qt::ToolTipRole:
 		if (index.column() == REMOVE)
 			return tr("Clicking here will remove this weight system.");
+		break;
 	}
 	return QVariant();
 }