rework(docs): better, more readable docs

docs/API_REFERENCE.md

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+# API Reference (Short)
+
+## Registry.Block
+
+```csharp
+RegisteredBlock Register(string id, BlockProperties properties)
+```
+
+Creates a block and its inventory item.
+
+## Registry.Item
+
+```csharp
+RegisteredItem Register(string id, ItemProperties properties)
+```
+
+Creates a new item.
+
+## Registry.Recipe
+
+```csharp
+void AddFurnace(string inputId, string outputId, float xp)
+```
+
+Adds a furnace recipe.
+
+## GameEvents
+
+```csharp
+event EventHandler<BlockBreakEventArgs> OnBlockBreak;
+event EventHandler<BlockPlaceEventArgs> OnBlockPlace;
+event EventHandler<ChatEventArgs> OnChat;
+event EventHandler<EntitySpawnEventArgs> OnEntitySpawn;
+event EventHandler<PlayerJoinEventArgs> OnPlayerJoin;
+```
+
+## Logger
+
+```csharp
+Logger.Debug(string message)
+Logger.Info(string message)
+Logger.Warning(string message)
+Logger.Error(string message)
+```
+
+## Identifier
+
+Namespaced IDs use `"namespace:path"` (for example, `"mymod:ruby_ore"`). If no namespace is provided, `"minecraft"` is assumed.