[css-values-4] Fix markup, link issues.

Author: fantasai

css-values-4/Overview.bs

@@ -457,7 +457,7 @@ Representing Interpolated Values: the ''mix()'' notation</h3>
 	whose syntax is defined as follows:
 
 	<pre class="prod">
-		mix( <<percentage>> ; <<start-value>> ; <<end-value )
+		mix( <<percentage>> ; <<start-value>> ; <<end-value>> )
 	</pre>
 
 	<dl dfn-for="mix()">
@@ -486,6 +486,14 @@ Representing Interpolated Values: the ''mix()'' notation</h3>
 	ISSUE: Define more precisely where mix() is allowed.
 	Is it a top-level functional notation only?
 	Or can it be nested more deeply in the grammar somehow?
+	(<a href="https://github.com/w3c/csswg-drafts/issues/6700">Issue 6700</a>)
+
+
+	ISSUE: What happens to values greater than 100% / less than 0%?
+	Do we clamp them to the range?
+	Interpolate past the range?
+	Make them invalid?
+	(<a href="https://github.com/w3c/csswg-drafts/issues/6701">Issue 6701</a>)
 
 <h3 id="combining-range">
 Range Checking</h3>