Describe your feature request

Match (regex::Match) represents a group match and has 4 methods, start, end, range, and as_str. While those methods are sufficient, I think len should be added. The reason simply is that I would prefer to use start + len rather than end, because I can't tell immediately if end refers to the last character or the 1 + the last character (it refers to 1 + the last character).

For instance, if I'm replacing a match m from original sting original_str, I would use:

original_str.replace_range(m.start() .. m.start() + m.len(), "foo")

rather than

original_str.replace_range(m.start()..m.end(), "foo")

I'm sure there are other instances where developers would prefer to use a len method, instances that make more sense than mine.