Add normailizeNormals doc.

docs/api/core/BufferGeometry.html

@@ -110,9 +110,10 @@
 		You need to call this when you want the bufferGeometry removed while the application is running.
 		</div>
 
-		<h3>.normalizeNormals() [page:todo]</h3>
+		<h3>.normalizeNormals()</h3>
 		<div>
-		todo
+        Every normal vector in a geometry will have a magnitude of 1.
+        This will correct lighting on the geometry surfaces.
 		</div>
 
 		<h2>Source</h2>