Change from 'I' to 'we'

The book seems to mix together singular and plural first person POV. I suggest we clean it up to use 'we' everywhere. At least to my ears this seems more professional and consistent with how much documentation is written.

The issue identifies the book as the scope but names no files or tests. Search the book text for singular first-person “I”, review each occurrence in context, and finish when the first-person voice is consistently “we” throughout.

Written by the indexing model from the issue text.