[ci skip] changelog: added a table of contents

generated using https://ecotrust-canada.github.io/markdown-toc/

changelogs/4.0-snapshot.md

@@ -2,6 +2,58 @@
 
 This major version features substantial changes throughout the core, including significant API changes, new world format support, performance improvements and a network revamp.
 
+## Contents
+* [Core](#core)
+  + [General](#general)
+  + [World handling](#world-handling)
+    - [Interface](#interface)
+    - [Functional](#functional)
+    - [Performance](#performance)
+  + [Logger revamp](#logger-revamp)
+  + [Network](#network)
+    - [Minecraft Bedrock packet encryption](#minecraft-bedrock-packet-encryption)
+    - [Packet receive error handling has been overhauled](#packet-receive-error-handling-has-been-overhauled)
+    - [New packet handler system](#new-packet-handler-system)
+* [API](#api)
+  + [General](#general-1)
+  + [Block](#block)
+  + [Command](#command)
+  + [Entity](#entity)
+    - [General](#general-2)
+    - [Effect](#effect)
+    - [Removal of runtime entity NBT](#removal-of-runtime-entity-nbt)
+    - [Entity creation](#entity-creation)
+    - [WIP removal of entity network metadata](#wip-removal-of-entity-network-metadata)
+  + [Event](#event)
+    - [Internal event system no longer depends on `Listener`s](#internal-event-system-no-longer-depends-on-listeners)
+    - [Default cancelled handling behaviour has changed](#default-cancelled-handling-behaviour-has-changed)
+    - [`PlayerPreLoginEvent` changes](#playerpreloginevent-changes)
+    - [Other changes](#other-changes)
+  + [Inventory](#inventory)
+  + [Item](#item)
+    - [General](#general-3)
+    - [NBT handling](#nbt-handling)
+    - [Enchantment](#enchantment)
+  + [Lang](#lang)
+  + [Network](#network-1)
+  + [Permission](#permission)
+  + [Player](#player)
+  + [Plugin](#plugin)
+  + [Scheduler](#scheduler)
+    - [Thread-local storage for AsyncTasks](#thread-local-storage-for-asynctasks)
+    - [Other changes](#other-changes-1)
+  + [Server](#server)
+  + [Level / World](#level---world)
+    - [General](#general-4)
+    - [Particles](#particles)
+    - [Sounds](#sounds)
+  + [Utils](#utils)
+* [Gameplay](#gameplay)
+  + [Blocks](#blocks)
+  + [Items](#items)
+
+<small><i><a href='http://ecotrust-canada.github.io/markdown-toc/'>Table of contents generated with markdown-toc</a></i></small>
+
 ## Core
 ### General
 - A new "plugin greylist" feature has been introduced, which allows whitelisting or blacklisting plugins from loading.