[enhancement] use a DocString to enhance the test report description

[undeadgrishnackh]

Hi, I'm being using your awesome pytest-describe-it lib from a while and I love it because it allows me to have a multi-dimensional test file like in Jest 😍. The unique thing I miss here is the possibility to tune the test report with a more descriptive title. The actual behavior is this one:

I'd love to see instead this one:

Maybe it looks like a naive feature, but it'd add a certain degree of customization that would make your lib even more attractive. thanks in advance. Mike