Implement std::error::Error for Error

[OhKannaDuh]

This PR implements std::error::Error for the Error enum.

Since this already had the Display impl, adding this allows it to integrate with error handling libs such anyhow.

// This
resources.parsed::<Lvb>(&lvb_path).map_err(anyhow::Error::msg)?;
// Becomes
resources.parsed::<Lvb>(&lvb_path)?;

Just a little bit of sugar.

[redstrate]

Thanks! Simple and great fix