Replit to be removed throughout book: RST & PRETEXT

[Austing767]

Any Replit code to be removed throughout the book

The pretext book does not contain any Replit blocks of code. However, Dr Jan has requested we at least look :) The RST version of the book contains some instances of Replit being used. Specific examples I believe to be included are in the output section/file handling, but I am uncertain of any other areas.