forked from microsoft/GSL
2231d733c6
- `s[s.size() - 1]` is wrong for empty `s`, so `Expects(s.size() > 0)`
- no hard coded `'\0'`but `value_type{}`
- hard code `empty()` to return `false`
- simplify `as_string_span`: can never be `empty`
- clarify comment on `ensure_z`