chore(grid): re-add width requirement for virtual columns, I killed it while rebasing

Author: marin-bratanov

components/grid/columns/virtual.md

@@ -31,6 +31,7 @@ To enable Virtualized Columns:
     * This will enable horizontal scrollbar which is required. You can read more about the scrolling behavior of the grid in the [Grid Column Width Behavior]({%slug grid-columns-width%}) article.
 1. Set the `RowHeight` so that the content of all cells fits in the row. For more information see the [Notes](#notes) section.
 1. Set the `Height` of the Grid in `px`. For more information see the [Notes](#notes) section.
+1. Set the `Width` parameter of the Grid in `px`.