error message when --base-k-step == -max-k-step #6094

The error message when --base-k-step == --max-k-step is a bit confusing:

ERROR: Please specify --base-k-step smaller than max-k-step if you want to use incremental verification.

It would be helpful if it said "smaller than max-k-step - 1", and I think the "if you want to use incremental verification" could be dropped, because it could be confused with --incremental-bmc.

Command line:
esbmc --loop-invariant --base-k-step 2 --max-k-step 2 while-inc1-3.cpp

-mark