Fuzzware cov: Indicate that more covering files are present

[Scepticz]

fuzzware cov -n 5 allows printing multiple files which cover a specific basic block. However, the default is -n 1, which leads to the user to believe that only one covering file is present. We may want to provide an indication that there are more inputs achieve the specified coverage. This could be as simple as printing ... after the output if we have not reached the end of all coverage traces, yet. We can also change found to displaying to indicate that not all are shown.