Properly fix JavaDoc linting issues

Fixes our own, and upstream's, issues with the stricter Java 8 JavaDoc
linter.

Also removes the destroystokyo-release maven repository. I'm not sure
why I added it originally, but it's unnecessary now.

Spigot-API-Patches/Custom-replacement-for-eaten-items.patch

@@ -5,14 +5,23 @@ Subject: [PATCH] Custom replacement for eaten items
 
 
 diff --git a/src/main/java/org/bukkit/event/player/PlayerItemConsumeEvent.java b/src/main/java/org/bukkit/event/player/PlayerItemConsumeEvent.java
-index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+index 8ab76b1d..7d28155b 100644
 --- a/src/main/java/org/bukkit/event/player/PlayerItemConsumeEvent.java
 +++ b/src/main/java/org/bukkit/event/player/PlayerItemConsumeEvent.java
+@@ -0,0 +0,0 @@ import org.bukkit.event.Cancellable;
+ import org.bukkit.event.HandlerList;
+ import org.bukkit.inventory.ItemStack;
+ 
++import javax.annotation.Nullable;
++
+ /**
+  * This event will fire when a player is finishing consuming an item (food,
+  * potion, milk bucket).
 @@ -0,0 +0,0 @@ public class PlayerItemConsumeEvent extends PlayerEvent implements Cancellable {
      private static final HandlerList handlers = new HandlerList();
      private boolean isCancelled = false;
      private ItemStack item;
-+    private ItemStack replacement; // Paper
++    @Nullable private ItemStack replacement; // Paper
  
      /**
       * @param player the player consuming
@@ -24,7 +33,10 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    /**
 +     * Return the custom item stack that will replace the consumed item, or null if no
 +     * custom replacement has been set (which means the default replacement will be used).
++     *
++     * @return The custom item stack that will replace the consumed item or null
 +     */
++    @Nullable
 +    public ItemStack getReplacement() {
 +        return this.replacement;
 +    }
@@ -32,8 +44,10 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +    /**
 +     * Set a custom item stack to replace the consumed item. Pass null to clear any custom
 +     * stack that has been set and use the default replacement.
++     *
++     * @param replacement Replacement item to set, null to clear any custom stack and use default
 +     */
-+    public void setReplacement(ItemStack replacement) {
++    public void setReplacement(@Nullable ItemStack replacement) {
 +        this.replacement = replacement;
 +    }
 +    // Paper end