Codechange: support strongly typed pool element IDs in squirrel/saveload

src/saveload/saveload.h

@@ -1318,6 +1318,7 @@ int64_t ReadValue(const void *ptr, VarType conv);
 void WriteValue(void *ptr, VarType conv, int64_t val);
 
 void SlSetArrayIndex(uint index);
+static void SlSetArrayIndex(const ConvertibleThroughBase auto &index) { SlSetArrayIndex(index.base()); }
 int SlIterateArray();
 
 void SlSetStructListLength(size_t length);