Fix deprecated code warnings

[norrs]

Warnings about stuff that is deprecated - hopefully correct.
Some ruby guru can probably confirm.

I couldn't catch this deprecation error when running the tests for rhapr:

Using `s` as a shortcut for the DocumentationFormatter is deprecated. Use `d`, `doc`, or `documentation` instead.


If you need more of the backtrace for any of these deprecations to
identify where to make the necessary changes, you can configure
`config.raise_errors_for_deprecations!`, and it will turn the
deprecation warnings into errors, giving you the full backtrace.

1 deprecation warning total

as providing config.raise_errors_for_deprecations! in spec_helper.rb for rhapr didn't help.