//! Total sub-slicing of the one source.
//!
//! Every L1 string is a slice of the parsed source, and spans are recovered
//! from pointers. Offsets the builders compute sit on ASCII delimiters, so
//! these ranges are always char-boundary ranges of `src`; should one not be,
//! the fallback is still a (zero-width) slice of `src` rather than a panic or
//! a foreign string.
/// `src[start..end]`, or the empty slice at `src`'s start.
pub
/// `src[start..]`, or the empty slice at `src`'s start.
pub
/// The zero-width slice at `src`'s start.