Documentation discrepancy

[cailloumajor]

Hello. First of all, thank you for those great libraries.

Unless I misunderstand, the statements of lines 135-140 in the extract below do not reflect how the code is doing.

msgpack-rust/rmp/src/encode/sint.rs

Lines 132 to 170 in f4ad0d0

	/// Encodes and attempts to write an `i64` value into the given write using the most efficient
	/// representation, returning the marker used.
	///
	/// This function obeys the MessagePack specification, which requires that the serializer SHOULD use
	/// the format which represents the data in the smallest number of bytes, with the exception of
	/// sized/unsized types.
	///
	/// Note, that the function will **always** use signed integer representation even if the value can
	/// be more efficiently represented using unsigned integer encoding.
	///
	/// The first byte becomes the marker and the others (if present, up to 9) will represent the data
	/// itself.
	///
	/// # Errors
	///
	/// This function will return `ValueWriteError` on any I/O error occurred while writing either the
	/// marker or the data.
	pub fn write_sint<W: RmpWrite>(wr: &mut W, val: i64) -> Result<Marker, ValueWriteError<W::Error>> {
	match val {
	val if -32 <= val && val < 0 => {
	write_nfix(wr, val as i8)
	.and(Ok(Marker::FixNeg(val as i8)))
	.map_err(ValueWriteError::InvalidMarkerWrite)
	}
	val if -128 <= val && val < -32 => write_i8(wr, val as i8).and(Ok(Marker::I8)),
	val if -32768 <= val && val < -128 => write_i16(wr, val as i16).and(Ok(Marker::I16)),
	val if -2147483648 <= val && val < -32768 => write_i32(wr, val as i32).and(Ok(Marker::I32)),
	val if val < -2147483648 => write_i64(wr, val).and(Ok(Marker::I64)),
	val if 0 <= val && val < 128 => {
	write_pfix(wr, val as u8)
	.and(Ok(Marker::FixPos(val as u8)))
	.map_err(ValueWriteError::InvalidMarkerWrite)
	}
	val if val < 256 => write_u8(wr, val as u8).and(Ok(Marker::U8)),
	val if val < 65536 => write_u16(wr, val as u16).and(Ok(Marker::U16)),
	val if val < 4294967296 => write_u32(wr, val as u32).and(Ok(Marker::U32)),
	val => write_u64(wr, val as u64).and(Ok(Marker::U64)),
	}
	}