[css-color-5] color-adjuster not optional

Author: svgeesus

css-color-5/Overview.bs

@@ -715,7 +715,7 @@ Adjusting colors: the ''color-adjust'' function {#coloradjust}
 	Multiple color functions can be specified.
 
 	<pre class='prod'>
-		<dfn>color-adjust()</dfn> = color-adjust( <<color>> [ <<color-adjuster>> && [ in <<color-space>> ]? ]? )
+		<dfn>color-adjust()</dfn> = color-adjust( <<color>> <<color-adjuster>> && [ in <<color-space>> ]?  )
 	</pre>
 
 	<pre class='prod'>