Rollup merge of #143841 - jieyouxu:clippy-autolabel, r=fmease

Label clippy changes with `T-clippy`

- Commits {1,2} are just drive-by housekeeping, no functional changes.
- Commit 3 adds an autolabel for `src/tools/clippy` to be labelled with https://github.com/rust-lang/rust/labels/T-clippy.

r? `@apiraino` (or clippy, or anyone really)

Author: fmease