Tiny typo

Author: dejbug

css-grid-2/Overview.bs

@@ -2869,7 +2869,7 @@ Placing Grid Items</h2>
 			* If it has an explicit ''grid-row-start/span'' value,
 				its [=grid span=] is <dfn export lt="explicit grid span|explicit row span|explicit column span|explicit span">explicit</dfn>.
 			* Otherwise, its [=grid span=] is <dfn export lt="automatic grid span|automatic row span|automatic column span|automatic span">automatic</dfn>:
-				if is [=subgridded=] in that axis,
+				if it is [=subgridded=] in that axis,
 				its [=grid span=] is <a href="#subgrid-span">determined</a> from its <<line-name-list>>;
 				otherwise its [=grid span=] is 1.
 	</dl>