[FR] [DOC] Better docs for methods that abstracts the UEFI FFI with wrappers

[Flamitsu]

Is your feature request related to a problem? Please describe.
I need to scroll up or down in the UEFI spec to find the function description and that's a problem

Describe the solution you'd like
Whenever I find an error I would like to have the status code and possible errors or descriptions to know what happened.