Later chapter makes use of code that is removed in an earlier chapter

[arjansiddhpura]

Instructions and code mentioned in Chapter 12.6, where running the program with > to redirect the standard output stream to output.txt which should cause an error will in fact not show any errors printed in the file output.txt, given that in the previous Chapter 12.4, instructs to remove the println! statements from src/lib.rs and src/main.rs.