[css-grid-1] Maintain dfn ID. #3277

Author: fantasai

css-grid-1/Overview.bs

@@ -3928,7 +3928,7 @@ Resolve Intrinsic Track Sizes</h3>
 					set its <a>base size</a>
 					to the maximum of its items’ <a>minimum contributions</a>,
 					floored at zero.
-					The <dfn noexport>minimum contribution</dfn> of an item is
+					The <dfn noexport id="min-size-contribution">minimum contribution</dfn> of an item is
 					the outer size that would result from assuming
 					the item’s used <a>minimum size</a>
 					('min-width' or 'min-height', whichever matches the relevant axis)