[css-text-decor-3] Sync with css-text-4 text-shadowwording.

* Link to shadow list animation definition
* Drop redundant comment about color, covered by 'box-shadow' definition.

Author: fantasai

css-text-decor-3/Overview.bs

@@ -851,7 +851,7 @@ Text Shadows: the 'text-shadow' property</h2>
 	Computed value: either the keyword ''box-shadow/none'' or
 		a list, each item consisting of three absolute lengths
 		plus a computed color
-	Animation type: as [=shadow list=]
+	Animation type: <a href="https://www.w3.org/TR/web-animations-1/#animating-shadow-lists">as shadow list</a>
 	</pre>
 
 	This property accepts a comma-separated list of shadow effects
@@ -860,9 +860,6 @@ Text Shadows: the 'text-shadow' property</h2>
 	(But note that spread values and the ''box-shadow/inset'' keyword are not allowed.)
 	Each layer shadows the element's text and all its text decorations
 	(composited together).
-	If the color of the shadow is not specified,
-	it defaults to ''currentColor'',
-	i.e. the shadow’s color is taken from the element’s 'color' property.
 
 	The shadow effects are applied front-to-back:
 	the first shadow is on top.