Meet DocC documentation in Xcode

// A model representing a sloth.
public struct Sloth {
    // ...
}

/// A model representing a sloth.
public struct Sloth {
    // ...
}

/** 
 A model representing a sloth.
 */
public struct Sloth {
    // ...
}

/// Food that a sloth can consume.
///
/// Sloths love to eat the leaves and twigs they find in the rainforest canopy as they
/// slowly move around. To feed them these items, you can use the `twig`,
/// `regularLeaf` and `largeLeaf` default foods.
///
/// ```swift
/// superSloth.eat(.twig)
/// ```
public struct Food {
		// ...
}

/// A model representing a sloth.
public struct Sloth {
    /// Sleep in the specified habitat for a number of hours.
    ///
    /// - Parameters:
    ///     - habitat: The location for the sloth to sleep.
    ///     - numberOfHours: The number of hours for the sloth to sleep.
    /// - Returns: The sloth’s energy level after sleeping.
    mutating public func sleep(in habitat: Habitat, for numberOfHours: Int = 12) -> Int {
        energyLevel += habitat.comfortLevel * numberOfHours
        return energyLevel
    }
}

/// A model representing a sloth.
public struct Sloth {
    /// Eat the provided specialty sloth food.
    ///
    /// Sloths love to eat while they move very slowly through their rainforest habitats. They
    /// are especially happy to consume leaves and twigs, which they digest over long periods
    /// of time, mostly while they sleep.
    ///
    /// ```swift
    /// let flower = Sloth.Food(name: "Flower Bud", energy: 10)
    /// superSloth.eat(flower)
    /// ```
    ///
    /// - Parameters:
    ///   - food: The food for the sloth to eat.
    ///   - quantity: The quantity of the food for the sloth to eat.
    /// - Returns: The sloth's energy level after eating.
    mutating public func eat(_ food: Food, quantity: Int = 1) -> Int {
        energyLevel += food.energy * quantity
        return energyLevel
    }
}

/// A model representing a sloth.
public struct Sloth {
    /// The energy level of the sloth.
    public var energyLevel: EnergyLevel

    /// Sleep in the specified habitat for a number of hours.
    ///
    /// Each time the sloth sleeps, their ``energyLevel`` increases every hour by the
    /// habitat's ``Habitat/comfortLevel``.  
    ///
    /// - Parameters:
    ///     - habitat: The location for the sloth to sleep.
    ///     - numberOfHours: The number of hours for the sloth to sleep.
    /// - Returns: The sloth’s energy level after sleeping.
    mutating public func sleep(in habitat: Habitat, for numberOfHours: Int = 12) -> Int {
        energyLevel += habitat.comfortLevel * numberOfHours
        return energyLevel
    }
}

/// A model representing a sloth.
public struct Sloth {
    /// Eat the provided specialty sloth food.
    ///
    /// Sloths love to eat while they move very slowly through their rainforest habitats. They
    /// are especially happy to consume leaves and twigs, which they digest over long periods
    /// of time, mostly while they sleep.
    ///
    /// ```swift
    /// let flower = Sloth.Food(name: "Flower Bud", energy: 10)
    /// superSloth.eat(flower)
    /// ```
    ///
    /// When they eat food, a sloth's ``energyLevel`` increases by the food's
    /// ``Food/energy``. 
    ///
    /// - Parameters:
    ///   - food: The food for the sloth to eat.
    ///   - quantity: The quantity of the food for the sloth to eat.
    /// - Returns: The sloth's energy level after eating.
    mutating public func eat(_ food: Food, quantity: Int = 1) -> Int {
        energyLevel += food.energy * quantity
        return energyLevel
    }
}