Update MaterialLoader.js docs for #32315 (#32316)

src/loaders/MaterialLoader.js

@@ -29,7 +29,7 @@ import {
 import { error, warn } from '../utils.js';
 
 /**
- * Class for loading geometries. The files are internally
+ * Class for loading materials. The files are internally
  * loaded via {@link FileLoader}.
  *
  * ```js