Switch to using ForgeFlower for Paper Only mc-dev imports

ForgeFlower is better than Spigots FernFlower at decompiling the source.

However, in order to maintain the CraftBukkit patches, we must keep
using spigots for the primary.

However, for any file that we import on top of Spigots imported files
there is nothing stopping us from using better decompiled files.

So these changes will use ForgeFlower to maintain a better set of
decomped files, so anything we add on top of Paper can start off
in a better spot.

Spigot-Server-Patches/Add-PlayerUseUnknownEntityEvent.patch

@@ -5,20 +5,20 @@ Subject: [PATCH] Add PlayerUseUnknownEntityEvent
 
 
 diff --git a/src/main/java/net/minecraft/server/PacketPlayInUseEntity.java b/src/main/java/net/minecraft/server/PacketPlayInUseEntity.java
-index 77440ac81f..8711462e16 100644
+index a4b98c81f5..53d38ea40f 100644
 --- a/src/main/java/net/minecraft/server/PacketPlayInUseEntity.java
 +++ b/src/main/java/net/minecraft/server/PacketPlayInUseEntity.java
-@@ -0,0 +0,0 @@ import javax.annotation.Nullable;
+@@ -0,0 +0,0 @@ import java.io.IOException;
+ import javax.annotation.Nullable;
  
  public class PacketPlayInUseEntity implements Packet<PacketListenerPlayIn> {
- 
 -    private int a;
 +    private int a; public int getEntityId() { return this.a; } // Paper - add accessor
      private PacketPlayInUseEntity.EnumEntityUseAction action;
      private Vec3D c;
      private EnumHand d;
 diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
-index 3257f41713..096e4e0d8c 100644
+index 62f35d2672..306ef5bf79 100644
 --- a/src/main/java/net/minecraft/server/PlayerConnection.java
 +++ b/src/main/java/net/minecraft/server/PlayerConnection.java
 @@ -0,0 +0,0 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {