bob: Lock problem description to match current implementation
bob: Lock problem description to match current implementation

We need to be able to regenerate the exercise READMEs without
causing the README for 'bob' to drift.

A new rule has been added to the upstream problem specification,
and this hasn't yet been implemented in this track.

patricksjackson/xcpp,patricksjackson/xcpp,exercism/xcpp,exercism/xcpp