Rollup merge of #61095 - ehuss:update-cargo, r=alexcrichton

Update cargo

Update cargo

14 commits in c4fcfb725b4be00c72eb9cf30c7d8b095577c280..545f354259be4e9745ea00a524c0e4c51df01aa6
2019-05-15 19:48:47 +0000 to 2019-05-23 17:45:30 +0000
- Bump to 0.38.0 (rust-lang/cargo#6979)
- cargo package: detect new empty directories (rust-lang/cargo#6973)
- Add message caching. (rust-lang/cargo#6933)
- Fix typo (rust-lang/cargo#6974)
- Set `Finished` line correctly for debug=0. (rust-lang/cargo#6971)
- Clippy fixes (rust-lang/cargo#6970)
- Remove rustdoc `can_add_color_process`. (rust-lang/cargo#6968)
- Document new `doctest` field. (rust-lang/cargo#6965)
- Update some man pages that missed --offline. (rust-lang/cargo#6964)
- add public & private prop tests. (rust-lang/cargo#6962)
- zsh completion: Pull list of commands from cargo --list (rust-lang/cargo#6956)
- Change docs "inequality" for semver requirement. (rust-lang/cargo#6963)
- Update im-rc requirement from 12.1.0 to 13.0.0 (rust-lang/cargo#6959)
- Add `doctest` field into metadata (rust-lang/cargo#6953)

diff --cc Cargo.lock
Simple merge