[css-text-decor-4] Remove inaccurate note. w3c#7088

Author: fantasai

css-text-decor-4/Overview.bs

@@ -474,10 +474,6 @@ Text Decoration Shorthand: the 'text-decoration' property</h3>
 	in one declaration.
 	Omitted values are set to their initial values.
 
-	Note: A 'text-decoration' declaration that omits
-	both the 'text-decoration-color' and 'text-decoration-style' values
-	is backwards-compatible with CSS Levels 1 and 2.
-
 	<div class="example">
 		The following example underlines unvisited links with a solid blue
 		underline in CSS1 and CSS2 UAs and a navy dotted underline in CSS3 UAs.