Add Override annotations where appropriate

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/potion/CraftPotionBrewer.java

@@ -17,6 +17,7 @@ import org.bukkit.potion.PotionType;
 public class CraftPotionBrewer implements PotionBrewer {
     private static final Map<PotionType, Collection<PotionEffect>> cache = Maps.newHashMap();
 
+    @Override
     public Collection<PotionEffect> getEffects(PotionType damage, boolean upgraded, boolean extended) {
         if (cache.containsKey(damage))
             return cache.get(damage);