SPIGOT-1244, SPIGOT-6860, SPIGOT-6874: Various Javadoc and formatting fixes

By: Parker Hawke <hawkeboyz2@hotmail.com>

paper-api/src/main/java/org/bukkit/Fluid.java

@@ -3,11 +3,26 @@ package org.bukkit;
 import java.util.Locale;
 import org.jetbrains.annotations.NotNull;
 
+/**
+ * Represents a fluid type.
+ */
 public enum Fluid implements Keyed {
 
+    /**
+     * Stationary water.
+     */
     WATER,
+    /**
+     * Flowing water.
+     */
     FLOWING_WATER,
+    /**
+     * Stationary lava.
+     */
     LAVA,
+    /**
+     * Flowing lava.
+     */
     FLOWING_LAVA;
 
     private final NamespacedKey key;