Add support for retrieving JGRPP-only content from content service

See: https://github.com/OpenTTD/OpenTTD/pull/9541, 84cba1b8

src/network/network_content.cpp

@@ -208,7 +208,7 @@ void ClientNetworkContentSocketHandler::RequestContentList(ContentType type)
 	Packet *p = new Packet(PACKET_CONTENT_CLIENT_INFO_LIST);
 	p->Send_uint8 ((byte)type);
 	p->Send_uint32(0xffffffff);
-	p->Send_uint8 (1);
+	p->Send_uint8 (2);
 	p->Send_string("vanilla");
 	p->Send_string(_openttd_content_version);
 
@@ -216,11 +216,10 @@ void ClientNetworkContentSocketHandler::RequestContentList(ContentType type)
 	 * add a branch in the 'compatibility' list, to filter on this. If you want
 	 * your patchpack to be mentioned in the BaNaNaS web-interface, create an
 	 * issue on https://github.com/OpenTTD/bananas-api asking for this.
+	 */
 
-	p->Send_string("patchpack"); // Or what-ever the name of your patchpack is.
-	p->Send_string(_openttd_content_version_patchpack);
-
-	*/
+	p->Send_string("jgrpp");
+	p->Send_string(_openttd_release_version);
 
 	this->SendPacket(p);
 }