Rustdoc doesn't expand macros

[huonw]

This means the documentation for std::int is broken (similarly for the other primitive integer modules), since most of the functionality is created via a macro.

[lilyball]

This probably needs fixing before releasing 0.7 or newcomers will have a hard time.

[bblum]

Hmm, I think production-ready milestone? Bit of a big papercut, though.

[catamorphism]

@cmr Is this an issue with rustdoc_ng?

[emberian]

@catamorphism nope, rustdoc_ng expands macros.

[catamorphism]

Great! Closing.