Function resolve_source_spans 

pub fn resolve_source_spans<'a: 'b, 'b>(
    source: &'a str,
    changes: &'b [Change],
) -> impl Iterator<Item = Option<&'a str>> + 'b

Resolve the source spans from Changes and the source schema, for change kinds that have a meaningful source span (see Change::source_span). Source spans are always relative to the source schema, since a Change always goes from source to target. Yields None for changes without a source span.