Feature: [GS] Scriptable league tables (#10001)

(cherry picked from commit 5e14a20b3b)

src/saveload/extended_ver_sl.cpp

@@ -180,6 +180,7 @@ const SlxiSubChunkInfo _sl_xv_sub_chunk_infos[] = {
 	{ XSLFI_U64_TICK_COUNTER,       XSCF_NULL,                1,   1, "u64_tick_counter",          nullptr, nullptr, nullptr        },
 	{ XSLFI_LINKGRAPH_TRAVEL_TIME,  XSCF_NULL,                1,   1, "linkgraph_travel_time",     nullptr, nullptr, nullptr        },
 	{ XSLFI_LAST_LOADING_TICK,      XSCF_NULL,                1,   1, "last_loading_tick",         nullptr, nullptr, nullptr        },
+	{ XSLFI_SCRIPT_LEAGUE_TABLES,   XSCF_NULL,                1,   1, "script_league_tables",      nullptr, nullptr, "LEAE,LEAT"    },
 	{ XSLFI_NULL, XSCF_NULL, 0, 0, nullptr, nullptr, nullptr, nullptr },// This is the end marker
 };