Generic cleanup of warnings, whitespace and style.

By: Erik Broes <erikbroes@grum.nl>

paper-api/src/main/java/org/bukkit/event/weather/LightningStrikeEvent.java

@@ -7,6 +7,7 @@ import org.bukkit.event.Cancellable;
 /**
  * Stores data for lightning striking
  */
+@SuppressWarnings("serial")
 public class LightningStrikeEvent extends WeatherEvent implements Cancellable {
 
     private boolean canceled;

paper-api/src/main/java/org/bukkit/event/weather/ThunderChangeEvent.java

@@ -6,6 +6,7 @@ import org.bukkit.event.Cancellable;
 /**
  * Stores data for thunder state changing in a world
  */
+@SuppressWarnings("serial")
 public class ThunderChangeEvent extends WeatherEvent implements Cancellable {
 
     private boolean canceled;

paper-api/src/main/java/org/bukkit/event/weather/WeatherChangeEvent.java

@@ -6,6 +6,7 @@ import org.bukkit.event.Cancellable;
 /**
  * Stores data for weather changing in a world
  */
+@SuppressWarnings("serial")
 public class WeatherChangeEvent extends WeatherEvent implements Cancellable {
 
     private boolean canceled;

paper-api/src/main/java/org/bukkit/event/weather/WeatherEvent.java

@@ -6,6 +6,7 @@ import org.bukkit.event.Event;
 /**
  * Represents a Weather-related event
  */
+@SuppressWarnings("serial")
 public class WeatherEvent extends Event {
     protected World world;