Enums in Rust can combine unit, tuple and named field variants to represent a wide range of concepts. This challenge uses enums to represent playing cards in a card game.

You will implement a Card enum that can represent either:

• A face card (e.g., King, Queen, Jack), which is a unit variant.
• A numbered card with a value (e.g., 7 of Hearts), which is a tuple variant.

Create an enum Card with the following variants:

• King, Queen, Jack (unit variants for face cards).
• Numbered(u8, String) representing a numbered card with its value and suit.

Write a function card_description that takes a Card and returns a description of the card:

• For King, return "King".
• For Queen, return "Queen".
• For Jack, return "Jack".
• For Numbered(value, suit), return "{value} of {suit}", e.g., "7 of Hearts".
• Ignore error handling for this challenge.