Developer docs link is confusing

[jaraco]

I stumbled on pytest-tap through PyPI and I wanted to get started trying it out. I went to https://pypi.org/project/pytest-tap, but it didn't provide any guidance on how to use it. I'd installed it into my test suite, but nothing happened. I tried passing --tap (following the convention of so many other pytest plugins that required --{name} to be passed to enable the pytest-{name} plugin. So I followed the "Developer documentation" link, but that went to the tappy documentation, which didn't provide any guidance on how to use it. I was eventually able to find the README which provided the necessary command line parameter, --tap-stream.

I propose that the long_description should contain the README or at least link to it as the primary documentation and not present tappy docs as their own.

[mblayman]

Thanks for the report! That addition makes sense to me. I'd happily accept a PR that updates the long description to refer to the README.