According to https://www.w3.org/TR/css-grid-2/#placement-shorthands
when setting the 'grid-row' and 'grid-column' shorthand property to a
single <custom-ident> value, both 'grid-row-start'/'grid-column-start'
and 'grid-row-end'/'grid-column-end' should be set to that
<custom_ident>.
