Documentation on coverage incorrect

I was using proposed solution from [README](https://github.com/google/atheris#visualizing-python-code-coverage), trying to get coverage from existing corpora. But failed and keep experimenting with environment and other such things in containers, i was using.
But the problem was in `+1` directive in atheris_runs parameter, and causion not to use `$(ls corpus_dir | wc -l)`, cause it also should fail to generate coverage data. The thing is that for me it is completely the opposite, only `-atheris_runs=$(ls corpus_dir | wc -l)` generates coverage data, so i can generate reports.

I'm using python 3.11, atheris 3.0.0 and coverage 6.3.2