Panic in src/generics/inline/emph_pair.rs: "attempt to subtract with overflow"

[akavel]

When running on the following markdown file:

- _foo
  bar_

(minimized from original: https://github.com/akavel/garden/blob/631d69ae5984f520936de5d554d0416719a057cd/20250108-001-%40discbound-brands.%40bud.md)

got a panic like below:

thread 'main' panicked at C:\Users\Mateusz\.cargo\registry\src\index.crates.io-6f17d22bba15001f\markdown-it-0.6.1\src\generics\inline\emph_pair.rs:133:9:
attempt to subtract with overflow
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
error: process didn't exit successfully: `_rust.out/debug\garden-render.exe` (exit code: 101)