Extra blank line inserted before code blocks in doc comments

[shulaoda]

Summary

Doc comment formatting inconsistency when using wrap_comments = true with max_width = 20: an extra blank line is inserted before code blocks.

# rustfmt.toml
wrap_comments = true
max_width = 20

/// Some doc comment with code snippet:
///```
/// '\u{1F}
/// ```
pub struct Code {}

Additional Context

This issue was discovered while attempting to fix other issues in rust-lang/rustfmt.

The latest rustfmt (rustfmt 1.8.0-nightly (6ac1fcd7a3 2025-10-09)) produces the correct output without the extra blank line. This issue is being filed to track this regression and verify whether it gets fixed after the next sync from rust-lang/rustfmt to rust-lang/rust.