Function toggle_comments_multi 

pub fn toggle_comments_multi(
    content: &str,
    ranges: &[LineRange],
    force_mode: Option<&str>,
    start_delim: &str,
    end_delim: &str,
) -> String

Toggle comments using multi-line/block comment delimiters. For each merged range, wraps the content in start/end delimiters (commenting) or strips them (uncommenting). Force mode works the same as single-line.