suggestion: label namespaces on hover

[sophiajt]

Was thinking about how we hadn't added any text to the hover when you hover a namespace/crate etc and how it'll be more likely that people do that with the 2018 edition.

What if there was a hover text but it said something simple like "module"? Just so people know there is something there, and to keep looking for something with more info.

One step better would be to allow navigation to those locations. But, at the very least, just let them know that the system is working but there just isn't much useful information at that location.

[alexheretic]

Thanks to the recent work by @aloucks / #930 rls does now provide more for this case.

Here are some examples of rls master in atom

[sophiajt]

@alexheretic - perfect! that's even better than I was thinking. Will wait for it to hit nightly.

[Xanewok]

This seems to work and we can now go-to them, so I'll close this 🎉 (sometimes failing goto tracked at #1106)