Fix: NLA editor not being updated on using "Make Links" (Ctrl)+(L). We're emitting a ND_NLA_ACTCHANGE signal now to make that work.

Found while documenting the NLA for my upcoming book

source/blender/editors/object/object_relations.c

@@ -1635,6 +1635,7 @@ static int make_links_data_exec(bContext *C, wmOperator *op)
 
 	DAG_relations_tag_update(bmain);
 	WM_event_add_notifier(C, NC_SPACE | ND_SPACE_VIEW3D, CTX_wm_view3d(C));
+	WM_event_add_notifier(C, NC_ANIMATION | ND_NLA_ACTCHANGE, CTX_wm_view3d(C));
 	WM_event_add_notifier(C, NC_OBJECT, NULL);
 
 	return OPERATOR_FINISHED;