Auto merge of #141305 - matthiaskrgr:rollup-l6nwaht, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #140972 (Add TRACING_ENABLED to Machine and add enter_trace_span!())
 - #141282 (`core_float_math`: Move functions to `math` module)
 - #141288 (Get rid of unnecessary `BufDisplay` abstraction)
 - #141289 (use `Self` alias in self types rather than manually substituting it)
 - #141291 (link tracking issue in explicit-extern-abis.md)
 - #141294 (triagebot: ping me if rustdoc js is modified)
 - #141303 (Fix pagetoc inactive color in rustc book)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors