[css-flexbox-1] Cross-link 'white space' to css-text-3. #5146

Author: fantasai

css-flexbox-1/Overview.bs

@@ -607,7 +607,7 @@ Flex Items</h2>
 	and each contiguous sequence of child <a>text runs</a>
 	is wrapped in an <a>anonymous</a> <a>block container</a> <a>flex item</a>.
 	However, if the entire sequence of child <a>text runs</a> contains only
-	<a href="https://www.w3.org/TR/CSS2/text.html#white-space-prop">white space</a>
+	[=document white space characters=]
 	(i.e. characters that can be affected by the 'white-space' property)
 	it is instead not rendered (just as if its <a>text nodes</a> were ''display:none'').