plotter: correct documentation of the colour chosing options

Author: tremblap

local_docs/fluid.plotter.html

@@ -282,7 +282,7 @@ <h3 class='method_name' name='pointcolor'>pointcolor</h3>
 		<h5>Argument details:</h5>
 		<ul>
 			<li>text: <p>The identifier of the point to modify.</p></li>
-			<li>colour: <p>The class (0 to 7) or Pd colour value (999 -> RGB) for the point.</p></li>
+			<li>colour: <p>The class (0 to 10) for the point. Each class has a perceptually optimal colour, as documented in <a href="https://github.com/d3/d3-scale-chromatic/blob/main/src/categorical/category10.js">this article.</a></p></li>
 		</ul>
 	</div>
 	<div class='method_group'>