[ci skip] Cleanup events (#10202)

patches/api/Add-exception-reporting-event.patch

@@ -12,23 +12,26 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 @@ -0,0 +0,0 @@
 +package com.destroystokyo.paper.event.server;
 +
-+import com.google.common.base.Preconditions;
 +import org.bukkit.Bukkit;
 +import org.bukkit.event.Event;
 +import org.bukkit.event.HandlerList;
 +import com.destroystokyo.paper.exception.ServerException;
++import org.jetbrains.annotations.ApiStatus;
 +import org.jetbrains.annotations.NotNull;
 +
 +/**
 + * Called whenever an exception is thrown in a recoverable section of the server.
 + */
 +public class ServerExceptionEvent extends Event {
-+    private static final HandlerList handlers = new HandlerList();
-+    @NotNull private ServerException exception;
 +
++    private static final HandlerList HANDLER_LIST = new HandlerList();
++
++    @NotNull private final ServerException exception;
++
++    @ApiStatus.Internal
 +    public ServerExceptionEvent(@NotNull ServerException exception) {
 +        super(!Bukkit.isPrimaryThread());
-+        this.exception = Preconditions.checkNotNull(exception, "exception");
++        this.exception = exception;
 +    }
 +
 +    /**
@@ -38,18 +41,18 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     */
 +    @NotNull
 +    public ServerException getException() {
-+        return exception;
++        return this.exception;
 +    }
 +
 +    @NotNull
 +    @Override
 +    public HandlerList getHandlers() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +
 +    @NotNull
 +    public static HandlerList getHandlerList() {
-+        return handlers;
++        return HANDLER_LIST;
 +    }
 +}
 diff --git a/src/main/java/com/destroystokyo/paper/exception/ServerCommandException.java b/src/main/java/com/destroystokyo/paper/exception/ServerCommandException.java