Static lib support

[alloc33]

I wonder if there any way to generate dash docset for a linux kernel? There is no Cargo.toml, maybe some workaround using rustup?

[Robzz]

From a quick look at their makefiles it looks like they invoke rustdoc directly so cargo-docset would probably need a different mode of operation there for working with pre-generated rustdocs. The code is not exactly fresh in my mind right now, but IIRC it uses the file names to populate the docset index so the method should also work with pre-built docs and the existing code shouldn't be too hard to adapt.