Function difft::parse::syntax::split_atom_words

fn split_atom_words(
    content: &str,
    pos: &[SingleLineSpan],
    opposite_content: &str,
    opposite_pos: &[SingleLineSpan],
    kind: AtomKind
) -> Vec<MatchedPos>

Given the text content from a comment or strings, split it into MatchedPos values for the novel and unchanged words.

If there is negligible text in common with opposite_content, treat the whole content as a single novel region.