[css-color-4] dedup IDs

Author: svgeesus

css-color-4/Overview.bs

@@ -474,7 +474,7 @@ Resolving <<color>> Values</h3>
 			<pre class="lang-css"><span class="swatch" style="--color: rgb(77.61% 36.34% 2.45%)"></span>  "lab(52.2345% 40.1645 59.9971)"</pre>
 		</div>
 
-	<h4 id="resolving-color-values">Resolving values of the ''color()'' function</h4>
+	<h4 id="resolving-color-function-values">Resolving values of the ''color()'' function</h4>
 
 		The computed and used value
 		is the color in the specified [=colorspace=],