[css-text-4] Add warnings to word-boundary-*

Author: fantasai

css-text-4/Overview.bs

@@ -1003,6 +1003,10 @@ Detecting Word Boundaries: the 'word-boundary-detection' property</h4>
 		parsing/word-boundary-detection-valid.html
 	</wpt>
 
+	ISSUE: The design of this property is still being worked out.
+	Don't implement it just yet!
+	You can ask the editors about status if this is blocking you.
+
 	This property allows the author to decide
 	whether and how
 	the user agent must analyse the content
@@ -1407,6 +1411,10 @@ Making Word Boundaries Visible: the 'word-boundary-expansion' property</h4>
 	Animation type: discrete
 	</pre>
 
+	ISSUE: The design of this property is still being worked out.
+	Don't implement it just yet!
+	You can ask the editors about status if this is blocking you.
+
 	<wpt>
 		parsing/word-boundary-expansion-computed.html
 		parsing/word-boundary-expansion-invalid.html