fn collect_entries<'a>(&'a self) -> (BTreeMap<&'a str, Lines<'a>>, usize) {
        self.lines
            .iter()
            .map(String::as_str)
            .filter_map(ParsedLine::parse)
            .fold((BTreeMap::new(), 0), |(mut entries, max_width), parsed| {
                let new_width = max_width.max(parsed.line_num.len());
                entries
                    .entry(parsed.path)
                    .or_default()
                    .push((parsed.line_num, parsed.content));
                (entries, new_width)
            })
    }
Collect file entries and determine the maximum line number width
crates/forge_display/src/grep.rs