Material documentation update

update method is no longer available since r85
https://github.com/mrdoob/three.js/commit/e1be08e4d9a88154ee07583b2c7a72330232b35c#diff-f5eb8fcc970231604c15522381d9f59e

docs/api/materials/Material.html

@@ -326,11 +326,6 @@
 		Convert the material to three.js JSON format.
 		</div>
 
-		<h3>[method:null update]()</h3>
-		<div>
-		Call [method:null dispatchEvent]( { type: '[param:object update]' }) on the material.
-		</div>
-
 		<h2>Source</h2>
 
 		[link:https://github.com/mrdoob/three.js/blob/master/src/[path].js src/[path].js]