Merge pull request w3c#1937 from Semigradsky/patch-1

[css-color-4] Fix typo

Author: ewilligers

css-color-4/Overview.bs

@@ -2387,7 +2387,7 @@ Modifying Colors: the ''color-mod()'' function</h2>
 		the color is still chromatic
 		(and the return value is ''#33f'').
 
-		On the other hand, if X is a greenish gray like ''#787'',
+		On the other hand, if X is a greenish gray like ''#708070'',
 		which is represented in HWB as ''hwb(120deg, 44%, 50%)'',
 		the first operation will boost the sum of white and black to greater than ''100%'',
 		making it an <a>achromatic</a> gray