Add documentation to AttributedStringConvertible

Author: natestedman

Attributed/AttributedStringConvertible.swift

@@ -27,27 +27,35 @@ public protocol AttributedStringConvertible
 }
 
 // MARK: - String
+
+/// Swift's `String` is extended to conform to `AttributedStringConvertible`.
 extension String: AttributedStringConvertible
 {
+    /// Required to conform to `AttributedStringConvertible`.
     public var attributedString: NSAttributedString
     {
         return NSAttributedString(string: self)
     }
 
+    /// Required to conform to `AttributedStringConvertible`.
     public func attributedStringWithAddedAttributes(attributes: [String : AnyObject]) -> NSAttributedString
     {
         return NSAttributedString(string: self, attributes: attributes)
     }
 }
 
 // MARK: - NSAttributedString
+
+/// Foundation's `NSAttributedString` is extended to conform to `AttributedStringConvertible`.
 extension NSAttributedString: AttributedStringConvertible
 {
+    /// Required to conform to `AttributedStringConvertible`.
     public var attributedString: NSAttributedString
     {
         return self
     }
 
+    /// Required to conform to `AttributedStringConvertible`.
     public func attributedStringWithAddedAttributes(attributes: [String : AnyObject]) -> NSAttributedString
     {
         let mutable = NSMutableAttributedString(attributedString: self)