[css-color-4] Use lab() in example (w3c#6291)

Related to f1e9daa

Author: valtlai

css-color-4/Overview.bs

@@ -3605,9 +3605,9 @@ and ''xyz''.</h3>
 					These are exactly equivalent:
 
 					<pre class="lang-css">
-						<span class="swatch" style="--color: #7654CD"></span> #7654CD;
+						<span class="swatch" style="--color: #7654CD"></span> #7654CD
 						<span class="swatch" style="--color: #7654CD"></span> rgb(46.27% 32.94% 80.39%)
-						<span class="swatch" style="--color: #7654CD"></span> color(lab 44.36% 36.05 -58.99)
+						<span class="swatch" style="--color: #7654CD"></span> lab(44.36% 36.05 -58.99)
 						<span class="swatch" style="--color: #7654CD"></span> color(xyz 0.2005 0.14089 0.4472)
 					</pre>
 				</div>