Added more documentation

lib.php

@@ -25,6 +25,8 @@ function local_treestudyplan_extend_navigation(global_navigation $navigation) {
 	//    Studieplannen beheren|/local/treestudyplan/edit-plan.php
 
 	// Using some javascript magic we'll hide the links that are not accessible
+	// (Since the Output API does not easily support inline style tags, adding one through Javascript is easier,
+	//  and not much more complex than loading a separate stylesheet for each link we want to hide)
 	// we will add all the hrefs that should be hidden to this variable below
 	$hide_primary_hrefs = [];