Fix help.yml index-topics not working for non-console senders (#13193)

Author: roro1506HD

paper-server/src/main/java/org/bukkit/craftbukkit/help/CustomIndexHelpTopic.java

@@ -7,6 +7,7 @@
 import org.bukkit.help.HelpMap;
 import org.bukkit.help.HelpTopic;
 import org.bukkit.help.IndexHelpTopic;
+import org.jetbrains.annotations.NotNull;
 
 public class CustomIndexHelpTopic extends IndexHelpTopic {
     private List<String> futureTopics;
@@ -18,8 +19,21 @@ public CustomIndexHelpTopic(HelpMap helpMap, String name, String shortText, Stri
         this.futureTopics = futureTopics;
     }
 
+    @Override
+    public boolean canSee(@NotNull final CommandSender sender) {
+        this.computeTopics();
+
+        return super.canSee(sender);
+    }
+
     @Override
     public String getFullText(CommandSender sender) {
+        this.computeTopics();
+
+        return super.getFullText(sender);
+    }
+
+    private void computeTopics() {
         if (this.futureTopics != null) {
             List<HelpTopic> topics = new LinkedList<>();
             for (String futureTopic : this.futureTopics) {
@@ -31,7 +45,5 @@ public String getFullText(CommandSender sender) {
             this.setTopicsCollection(topics);
             this.futureTopics = null;
         }
-
-        return super.getFullText(sender);
     }
 }