[css-grid-1] Add a note clarifying intention of prioritization of tra…

…cks when distributing past growth limits. #3621

css-grid-1/Overview.bs

@@ -4277,6 +4277,12 @@ Distributing Extra Space Across Spanned Tracks</h4>
 					until it reaches the limit specified as the ''fit-content()'' argument,
 					after which it is treated as having a <a>fixed sizing function</a> of that argument.
 
+					Note: This step prioritizes the distribution of space
+					for accommodating space required
+					by the tracks’ [=min track sizing functions=]
+					beyond their current growth limits
+					based on the types of their [=max track sizing functions=].
+
 				<li>
 					For each affected track,
 					if the track’s |item-incurred increase| is larger than the track’s |planned increase|