[css-sizing-3] Surface comment about new behavior in a note.

Author: fantasai

css-sizing-3/Overview.bs

@@ -927,7 +927,7 @@ are defined below:
 			Note: This case was previous calculated from a 300x150 default size,
 			rather than the box's min size.
 			This is believed to be a better behavior,
-			and likely to be web compatible,
+			and likely to be Web-compatible,
 			but please send feedback to the CSSWG if there are any problems.
 			<!-- Brand new behavior not defined in CSS2 -->
 
@@ -944,8 +944,12 @@ are defined below:
 		* If the box has a <<length>> as its [=computed value|computed=]
 			[=minimum size=] ('min-width'/'min-height') in that dimension,
 			use that size.
-			<!-- New behavior made possible by auto initial value;
-				we think it's good, not 100% sure if Web-compatible. -->
+
+			Note: This author-controllable behavior is made possible
+			by the new ''min-width/auto'' value for the [=minimum size properties=].
+			This is believed to be a better behavior,
+			but it is not yet clear if it is Web-compatible,
+			so please send feedback to the CSSWG if there are any problems.
 
 		* Otherwise,
 			use ''300px'' for the width