Implement a reference label protocol for exercises so cross chapter reference labels are not the same. Meaning we don't want `#exr-01` used in both chapters 1 and 2 to refer tot he first exercise in chapters 1 and 2.
Implement a reference label protocol for exercises so cross chapter reference labels are not the same.
Meaning we don't want
#exr-01used in both chapters 1 and 2 to refer tot he first exercise in chapters 1 and 2.