Rename LOGIN_DOWNSTREAM_JS5REMOTE to JS5REMOTE_DOWNSTREAM

I've also removed the comment - I'm going to have to do something
similar for CREATE_DOWNSTREAM, and I think it's a bit more obvious with
the more distinctive name.

archive/src/main/kotlin/org/openrs2/archive/cache/OsrsJs5ChannelInitializer.kt

@@ -12,7 +12,7 @@ public class OsrsJs5ChannelInitializer(private val handler: OsrsJs5ChannelHandle
         ch.pipeline().addLast(
             ReadTimeoutHandler(30),
             Rs2Encoder(Protocol.LOGIN_UPSTREAM),
-            Rs2Decoder(Protocol.LOGIN_DOWNSTREAM_JS5REMOTE)
+            Rs2Decoder(Protocol.JS5REMOTE_DOWNSTREAM)
         )
         ch.pipeline().addLast("handler", handler)
     }

game/src/main/kotlin/org/openrs2/game/net/login/LoginChannelHandler.kt

@@ -50,7 +50,7 @@ public class LoginChannelHandler @Inject constructor(
 
     private fun handleInitJs5RemoteConnection(ctx: ChannelHandlerContext, msg: LoginRequest.InitJs5RemoteConnection) {
         val encoder = ctx.pipeline().get(Rs2Encoder::class.java)
-        encoder.protocol = Protocol.LOGIN_DOWNSTREAM_JS5REMOTE
+        encoder.protocol = Protocol.JS5REMOTE_DOWNSTREAM
 
         if (msg.build != BUILD) {
             ctx.write(LoginResponse.ClientOutOfDate).addListener(ChannelFutureListener.CLOSE)

protocol/src/main/kotlin/org/openrs2/protocol/Protocol.kt

@@ -46,14 +46,7 @@ public class Protocol(vararg codecs: PacketCodec<*>) {
             IpLimitCodec
         )
 
-        /**
-         * Unfortunately the Js5Ok packet's opcode overlaps with the exchange
-         * session keys opcode - the only case where this happens. We therefore
-         * have two LOGIN_DOWNSTREAM protocols to avoid ambiguity: one for
-         * responses to the InitJs5RemoteConnection packet, and one for
-         * responses to all other login packets.
-         */
-        public val LOGIN_DOWNSTREAM_JS5REMOTE: Protocol = Protocol(
+        public val JS5REMOTE_DOWNSTREAM: Protocol = Protocol(
             Js5OkCodec,
             ClientOutOfDateCodec,
             ServerFullCodec,