Add documentation for data in API

Author: renvins

api/src/main/java/it/renvins/serverpulse/api/data/SyncMetricsSnapshot.java

@@ -2,6 +2,7 @@
 
 import java.util.Map;
 
+
 public class SyncMetricsSnapshot {
 
     private final double[] tps;

api/src/main/java/it/renvins/serverpulse/api/data/WorldData.java

@@ -1,5 +1,9 @@
 package it.renvins.serverpulse.api.data;
 
+/**
+ * Represents data about a world in the server.
+ * This class contains information about the number of entities and loaded chunks in a world.
+ */
 public class WorldData {
 
     private final int entities;