[Issue 12344] .di generation doesn't include contracts in interfaces

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=12344
Issue 12344 depends on issue 6549, which changed state.

Issue 6549 Summary: Implement contracts without implementation.
https://issues.dlang.org/show_bug.cgi?id=6549

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

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