Rollup merge of #78493 - ehuss:update-cargo, r=ehuss

Update cargo

8 commits in dd83ae55c871d94f060524656abab62ec40b4c40..becb4c282b8f37469efb8f5beda45a5501f9d367
2020-10-20 19:31:26 +0000 to 2020-10-28 16:41:55 +0000
- List available packages if providing `--package` with an empty value (rust-lang/cargo#8808)
- Add a future-compatibility warning on allowed feature name characters. (rust-lang/cargo#8814)
- New namespaced features implementation. (rust-lang/cargo#8799)
- Remove redundant "For example, " (rust-lang/cargo#8810)
- Document platform-specific build-dependencies (rust-lang/cargo#8809)
- Remove some unused code. (rust-lang/cargo#8807)
- Some minor clippy fixes. (rust-lang/cargo#8804)
- Update TOML website links. (rust-lang/cargo#8803)

cargo @ becb4c28

-Subproject commit dd83ae55c871d94f060524656abab62ec40b4c40
+Subproject commit becb4c282b8f37469efb8f5beda45a5501f9d367