cargo-docset does not support virtual manifest workspaces

[lilyball]

Describe the bug
When using a workspace that uses a virtual manifest, cargo-docset docset panics with

thread 'main' panicked at 'Cargo.toml doesn't have a package table', src/commands/generate.rs:343:18

A virtual manifest workspace is one without a "root" package. cargo doc works just fine here (cargo doc --workspace --open just opens to the first crate in the workspace members list, but it includes all the crates).

It appears that cargo-docset is attempting to look up the root package name here. For virtual manifest workspaces, it would be really great if it could support a flag to provide a docset name, and default to the name of the containing folder. Until such time as cargo doc synthesizes a proper landing page for the docset, cargo-docset could just default to the first member crate exactly as cargo doc does (or it could synthesize a common landing page).

As a workaround, I can invoke cargo-docset docset --all from one of the member crates, but the resulting docset is named after that member crate.

To Reproduce
Steps to reproduce the behavior:

1. Make a virtual manifest workspace (a workspace whose Cargo.toml contains a [workspace] section but not a [package] section)
2. From the root of that workspace, run cargo-docset docset.

Expected behavior
It should build a docset for the workspace.

[Robzz]

Hi, thanks for the bug report. I'll try and look into that soon.

[Robzz]

It should now work. I haven't provided a flag to rename the docset yet, so the docset's name will be the same as the directory containing the virtual manifest, but it's one of the flags I was planning to add, I'll try to slip it in before the next release, as there's a couple of things I want to do before then. I'm hoping to ship the release by the end of next week :)