Ethernet compliance codes can be emitted as strings that we can't parse

[bnaecker]

We're using Display and FromStr to read / write the Ethernet compliance codes when they appear in an API. Here are the impls:

transceiver-control/decode/src/datapath.rs

Lines 151 to 189 in 1f94d98

	impl fmt::Display for EthernetComplianceCode {
	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
	match self.0 {
	0b0000_0001 => write!(f, "40G Active Cable"),
	0b0000_0010 => write!(f, "40GBASE-LR4"),
	0b0000_0100 => write!(f, "40GBASE-SR4"),
	0b0000_1000 => write!(f, "40GBASE-CR4"),
	0b0001_0000 => write!(f, "10GBASE-SR"),
	0b0010_0000 => write!(f, "10GBASE-LR"),
	0b0100_0000 => write!(f, "10GBASE-LRM"),
	x => write!(f, "Unknown (0x{x:02x})"),
	}
	}
	}
	impl From<EthernetComplianceCode> for String {
	fn from(value: EthernetComplianceCode) -> Self {
	format!("{value}")
	}
	}
	#[cfg(any(feature = "api-traits", test))]
	impl std::str::FromStr for EthernetComplianceCode {
	type Err = &'static str;
	fn from_str(value: &str) -> Result<Self, Self::Err> {
	const ERR: &str = "Unknown or malformed Ethernet compliance code";
	match value {
	"40G Active Cable" => Ok(Self(0b0000_0001)),
	"40GBASE-LR4" => Ok(Self(0b0000_0010)),
	"40GBASE-SR4" => Ok(Self(0b0000_0100)),
	"40GBASE-CR4" => Ok(Self(0b0000_1000)),
	"10GBASE-SR" => Ok(Self(0b0001_0000)),
	"10GBASE-LR" => Ok(Self(0b0010_0000)),
	"10GBASE-LRM" => Ok(Self(0b0100_0000)),
	_ => Err(ERR),
	}
	}
	}

These two don't match. If we get an unknown code from the module, we write it out as Unknown (0xAA). But we have a wildcard match in the FromStr impl that will catch that and return an error. We need to parse it the same way we emit it.