Auto merge of #120196 - matthiaskrgr:rollup-id2zocf, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #120005 (Update Readme)
 - #120045 (Un-hide `iter::repeat_n`)
 - #120128 (Make stable_mir::with_tables sound)
 - #120145 (fix: Drop guard was deallocating with the incorrect size)
 - #120158 (`rustc_mir_dataflow`: Restore removed exports)
 - #120167 (Capture the rationale for `-Zallow-features=` in bootstrap.py)
 - #120174 (Warn users about limited review for tier 2 and 3 code)
 - #120180 (Document some alternatives to `Vec::split_off`)

Failed merges:

 - #120171 (Fix assume and assert in jump threading)

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

Author: bors