update protocol packet definitions: replace value receivers with pointer receivers in PacketID methods, expand FixedBitSet size from 8 to 256 bits, and remove outdated documentation files

pkg/protocol/packet/game/server/set_test_block.go

@@ -12,7 +12,7 @@ type SetTestBlock struct {
 	Message  string
 }
 
-func (SetTestBlock) PacketID() packetid.ServerboundPacketID {
+func (*SetTestBlock) PacketID() packetid.ServerboundPacketID {
 	return packetid.ServerboundSetTestBlock
 }