Change return type of lifecycle hooks in minitest to be void

[stevegeek]

Hi all, many thanks for all the work on RBS.

I am proposing a change to the Lifecycle hooks of Minitest::Test so that they are void instead of nil.

Otherwise any time we use the setup hook for example, we need to explicitly return nil but normally we don't care what we return from these methods. The return value is not used in minitest I believe (https://github.com/minitest/minitest/blob/master/lib/minitest/test.rb#L91)

I wasn't really sure about how to use the assert_send_type test helper but I tried to write a test anyway.

Let me know what you think.

[ksss]

I agree with you.
These types are generated by rbs prototype rb, so there is no special intention.
LGTM!

[stevegeek]

Thanks @ksss !