Rebuild for crate: bdk 0.6.0

[notmandatory]

Crate name: bdk
Build failure link: https://docs.rs/crate/bdk/0.6.0/builds

Additional details:
I've verified our docs will build correctly with the latest nightly 2021-04-15, our docs were impacted by rust-lang/rust#84162, fixed by rust-lang/rust#84130

[jyn514]

I added it to the queue.

[notmandatory]

Docs rebuilt successfully. Thanks!