Auto merge of #70371 - Centril:rollup-ywi1vo3, r=Centril

Auto merge of #70371 - Centril:rollup-ywi1vo3, r=Centril

Rollup of 8 pull requests

Successful merges:

 - #70023 (clean up E0436 explanation)
 - #70234 (#[track_caller] on core::ops::{Index, IndexMut}.)
 - #70241 (Miri: move ModifiedStatic to ConstEval errors)
 - #70342 (IoSlice/IoSliceMut should be Send and Sync)
 - #70350 (Request "-Z unstable-options" for unstable options)
 - #70355 (Clean up E0454)
 - #70359 (must_use on split_off)
 - #70368 (Mark hotplug_codegen_backend as ignore-stage1)

Failed merges:

r? @ghost