[css-grid-1] Fix size/contribution error, clarify antecedent. w3c#3565

Author: fantasai

css-grid-1/Overview.bs

@@ -3968,8 +3968,9 @@ Resolve Intrinsic Track Sizes</h3>
 					is (for this purpose) its <a lt="min-content contribution">min-</a>/<a>max-content contribution</a> (accordingly);
 					limited by the <a>max track sizing function</a>
 					if that is <a lt="fixed sizing function">fixed</a>,
-					else by it's own <a lt="min-content size">min-content</a>/<a>max-content size</a>
-					if that is ''grid-template-columns/min-content''/''grid-template-columns/max-content'';
+					else by it's own <a lt="min-content contribution">min-</a>/<a>max-content contribution</a>
+					if the <a>max track sizing function</a>
+					is ''grid-template-columns/min-content''/''grid-template-columns/max-content'';
 					and ultimately floored by its <a>minimum contribution</a> (defined below).
 
 					Otherwise,