Merge pull request #4389 from xiaochengh/patch-1

[css-values] Change MAY into MUST regarding calc() on table

Author: tabatkins

css-values-4/Overview.bs

@@ -3522,7 +3522,7 @@ Computed Value</h3>
 	math expressions mixing both percentages and lengths for widths and heights on
 	table columns, table column groups, table rows, table row groups, and table cells
 	in both auto and fixed layout tables
-	MAY be treated as if ''width/auto'' had been specified.
+	MUST be treated as if ''width/auto'' had been specified.
 
 
 <h3 id='calc-range'>