[css-ui-4] Update comment about .cur and .ico support for cursors

Author: frivoal

css-ui-4/Overview.bs

@@ -786,10 +786,12 @@ Styling the Cursor: the 'cursor' property</h4>
 					Support for non-naturally sized SVG was downgraded from mandatory to optional due
 					to lack of implementations.
 
-					Note: At the time of writing this specification (spring 2015),
-					the only file formats supported for cursors in common desktop browsers are
+					Note: For a number of years,
+					the only file formats supported for cursors in common desktop browsers were
 					the .ico and .cur file formats, as designed by Microsoft.
-					For compatibility with legacy content,
+					Although this is no longer the case
+					(PNG and SVG have broad support),
+					for compatibility with legacy content,
 					UAs are encouraged to support these,
 					even though the lack of an open specification
 					makes it impossible to have a normative requirement