rls no longer builds after rust-lang/rust#84767

[rust-highfive]

Hello, this is your friendly neighborhood mergebot.
After merging PR #84767, I observed that the tool rls no longer builds.
A follow-up PR to the repository https://github.com/rust-lang/rls is needed to fix the fallout.

cc @scottmcm, do you think you would have time to do the follow-up work?
If so, that would be great!

[scottmcm]

Sure, I can look at this one.

[scottmcm]

@Xanewok Thanks for merging racer-rust/racer#1167!

If I'm reading things right, I think I need a new crater release of it so I can update https://github.com/rust-lang/rls/blob/master/Cargo.toml#L46 ? If so, can you please make one of those?