/// Replacer describes types that can be used to replace matches in a string.
pub trait Replacer {
/// Returns a possibly owned string that is used to replace the match
- /// corresponding the the `caps` capture group.
+ /// corresponding to the `caps` capture group.
///
/// The `'a` lifetime refers to the lifetime of a borrowed string when
/// a new owned string isn't needed (e.g., for `NoExpand`).