Rollup merge of #113142 - the8472:opt-cstr-display, r=Mark-Simulacrum

optimize EscapeAscii's Display  and CStr's Debug

```
old:
    ascii::bench_ascii_escape_display_mixed      17.97µs/iter +/- 204.00ns
    ascii::bench_ascii_escape_display_no_escape 545.00ns/iter   +/- 6.00ns
new:
    ascii::bench_ascii_escape_display_mixed      4.99µs/iter +/- 56.00ns
    ascii::bench_ascii_escape_display_no_escape 91.00ns/iter  +/- 1.00ns
```

Author: matthiaskrgr