Controls whether proof attempts are printed during CCG analysis
If v is nil, no proof attempts will be printed during CCG
analysis. This is the default. If v is anything but nil, proofs will
be displayed. Fair warning: there is potentially a large amount of prover
output that might be displayed. It is probably better to use See set-ccg-inhibit-output-lst to un-inhibit 'query output to figure out
what lemmas might be needed to get a given query to go through.