Feature request: Expose `Unit` enum as `pub`

[Sheape]

Parsing unit from string is already implemented but the Unit enum isn't exposed as pub. I'm not sure if there any implications by simply changing it to pub aside from adding explicit documentation. Anyways, this is the actual missing piece to resolve nushell/nushell#15007. Feel free to close this issue if this is unreasonable or if it's not the goal of the project 😊
Otherwise, I can open a PR about this.

bytesize/src/parse.rs

Lines 162 to 185 in ac756bb

	impl str::FromStr for Unit {
	type Err = String;
	fn from_str(unit: &str) -> Result<Self, Self::Err> {
	match unit.to_lowercase().as_str() {
	"b" => Ok(Self::Byte),
	// power of tens
	"k" | "kb" => Ok(Self::KiloByte),
	"m" | "mb" => Ok(Self::MegaByte),
	"g" | "gb" => Ok(Self::GigaByte),
	"t" | "tb" => Ok(Self::TeraByte),
	"p" | "pb" => Ok(Self::PetaByte),
	"e" | "eb" => Ok(Self::ExaByte),
	// power of twos
	"ki" | "kib" => Ok(Self::KibiByte),
	"mi" | "mib" => Ok(Self::MebiByte),
	"gi" | "gib" => Ok(Self::GibiByte),
	"ti" | "tib" => Ok(Self::TebiByte),
	"pi" | "pib" => Ok(Self::PebiByte),
	"ei" | "eib" => Ok(Self::ExbiByte),
	_ => Err(format!("couldn't parse unit of {unit:?}")),
	}
	}
	}

[robjtede]

Would a non-exhaustive version be sufficient?

See #123