Remove useful comment

plugins/Toolbox/resources/qml/ToolboxDownloadsGrid.qml

@@ -9,8 +9,6 @@ import UM 1.1 as UM
 
 Column
 {
-    // HACK: GridLayouts don't render to the correct height with odd numbers of
-    // items, so if odd, add some extra space.
     height: childrenRect.height
     width: parent.width
     spacing: UM.Theme.getSize("default_margin").height