The checklist is what you'd be reading, usually a laminated one-page card kept in a convenient spot. The documentation that the checklist refers to is the full "user manual" for the plane, with things like the quick reference handbook (QRH) that includes the step-by-step procedures covering what to do for every single warning light, emergency condition, etc. Also "documentation" here could also cover the mandatory things you have to have in the plane like the airworthiness certificate, registration, FCC radio license, insurance certificate, etc.
So I guess the short answer to your question is yes, in this context the documentation and checklist are not the same thing.