Completions don't work for library crate with different lib name

[jwilm]

I encountered this when integrating multirust-rs. The crate's name is multirust-rs, and the Cargo.toml for the crate has

[lib]
name = "multirust"

In the consumer's code, we use an extern crate multirust; due to the name config. No completions are provided for the multirust:: namespace.

[jwilm]

Another example here is the rust-crypto crate which has lib.name = "crypto"