Remove cow_add_assign
@@ -596,7 +596,7 @@ impl<'a> WrapIterImpl<'a> {
// we will return the line with its line break after exiting the loop
if self.split + self.split_len < self.source.len() {
let mut line = self.create_result_line(wrapper);
- cow_add_assign(&mut line, &self.source[self.start..self.split]);
+ line += &self.source[self.start..self.split];
self.start = self.split + self.split_len;
self.line_width += wrapper.subsequent_indent.width();
