Ex09 lines 88-90 clarification

[whatthedev-eth]

If I understand the recursions correctly, I think comment lines 88-89 should instead say something like this:

# This part of the function is first reached when **length=1 (after return from length=0)**.
# Checking that the **current** value in the array ([array]) is not 0

and line 90 error message should instead be something like

with_attr error_message("**No value of the array should be 0**"):