[Bleeding] Moved DefaultHelpTopic and GenericCommandHelpTopic to public bukkit api.

By: rmichela <deltahat@gmail.com>

paper-api/src/main/java/org/bukkit/help/IndexHelpTopic.java

@@ -0,0 +1,63 @@
+package org.bukkit.help;
+
+import org.bukkit.ChatColor;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Player;
+import org.bukkit.help.HelpTopic;
+import org.bukkit.util.ChatPaginator;
+
+import java.util.Collection;
+
+/**
+ * This help topic generates a list of other help topics. This class is useful for adding your own
+ * index help topics.
+ */
+public class IndexHelpTopic extends HelpTopic {
+
+    private Collection<HelpTopic> allTopics;
+
+    /**
+     * Creates an index help topic from a collection of help topics. The index is displayed in the order of the
+     * topic collection's iterator. To enforce a particular order, use a sorted collection.
+     * @param topics The collection of topics to use display in an index.
+     */
+    public IndexHelpTopic(Collection<HelpTopic> topics) {
+        this.allTopics = topics;
+    }
+
+    public boolean canSee(CommandSender sender) {
+        return true;
+    }
+
+    public String getName() {
+        return "Overall";
+    }
+
+    public String getShortText() {
+        return "";
+    }
+
+    public String getFullText(CommandSender sender) {
+        StringBuilder sb = new StringBuilder();
+        for (HelpTopic topic : allTopics) {
+            if (topic.canSee(sender)) {
+                StringBuilder line = new StringBuilder();
+                line.append(ChatColor.GOLD);
+                line.append(topic.getName());
+                line.append(": ");
+                line.append(ChatColor.WHITE);
+                line.append(topic.getShortText());
+
+                String lineStr = line.toString().replace("\n", ". ");
+                if (sender instanceof Player && lineStr.length() > ChatPaginator.AVERAGE_CHAT_PAGE_WIDTH) {
+                    sb.append(lineStr.substring(0, ChatPaginator.AVERAGE_CHAT_PAGE_WIDTH - 3));
+                    sb.append("...");
+                } else {
+                    sb.append(lineStr);
+                }
+                sb.append("\n");
+            }
+        }
+        return sb.toString();
+    }
+}