Update references to distillery.init

[hrubi]

There were few leftovers in the documentation still referring to release.init.

Summary of changes

I'll review the commits, so I mostly want to understand the "why" rather than the "what"

Checklist

• New functions have typespecs, changed functions were updated
• Same for documentation, including moduledocs
• Tests were added or updated to cover changes
• Commits were squashed into a single coherent commit

Licensing/Copyright

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