Fix comment typo

examples/js/cameras/CombinedCamera.js

@@ -129,7 +129,7 @@ THREE.CombinedCamera.prototype.setFov = function( fov ) {
 
 };
 
-// For mantaining similar API with PerspectiveCamera
+// For maintaining similar API with PerspectiveCamera
 
 THREE.CombinedCamera.prototype.updateProjectionMatrix = function() {