Display multibyte e-expression headers

[zslayton]

Currently, inspect assumes all e-expressions will have a one-byte header:

ion-cli/src/bin/ion/commands/inspect.rs

Lines 458 to 466 in 03a3fc8

	fn inspect_eexp(&mut self, depth: usize, eexp: EExpression<AnyEncoding>) -> Result<()> {
	let mut formatter = BytesFormatter::new(
	BYTES_PER_ROW,
	vec![
	// TODO: Add methods to EExpression that allow nuanced access to its encoded spans
	// TODO: Length-prefixed and multibyte e-expression addresses
	IonBytes::new(BytesKind::MacroId, &eexp.span().bytes()[0..1]),
	],
	);

However, is only the case for invocations of user macros with an ID lower than 64.
Invocations of system macros are two bytes (0xEE 0x__), and invocations of macros with IDs >= 64 are at least two bytes.