Fix API documentation for common rules

[aherrmann]

Closes #1122

The rules haskell_library|binary|test are exposed through wrapper macros, the rules themselves are hidden. As a consequence the API documentation doesn't show the doc attribute of the rule attributes. This PR makes the attributes explicit in the wrapper macros, and moves the attribute documentation into the docstring of the wrapper macros. Unfortunately, wrapper macros cannot inherit rule documentation. See bazelbuild/stardoc#27

[aherrmann]

Rendered

[thufschmitt]

Thanks! It's a bit sad that we can't benefit from **kwargs anymore, but that's a more than decent traedoff