Add @discardableResult to UIView animates

I resisted, because why use these if you don’t intend to use the Guarantee? But it turns that I use these because their API is better than Apple’s where there are no default parameters.

Author: mxcl

Sources/UIView+Promise.swift

@@ -40,23 +40,28 @@ public extension UIView {
      - Returns: A promise that fulfills with a boolean NSNumber indicating
      whether or not the animations actually finished.
     */
+    @discardableResult
     static func animate(_: PMKNamespacer, duration: TimeInterval, delay: TimeInterval = 0, options: UIViewAnimationOptions = [], animations: @escaping () -> Void) -> Guarantee<Bool> {
         return Guarantee { animate(withDuration: duration, delay: delay, options: options, animations: animations, completion: $0) }
     }
 
+    @discardableResult
     static func animate(_: PMKNamespacer, duration: TimeInterval, delay: TimeInterval, usingSpringWithDamping damping: CGFloat, initialSpringVelocity: CGFloat, options: UIViewAnimationOptions = [], animations: @escaping () -> Void) -> Guarantee<Bool> {
         return Guarantee { animate(withDuration: duration, delay: delay, usingSpringWithDamping: damping, initialSpringVelocity: initialSpringVelocity, options: options, animations: animations, completion: $0) }
     }
 
+    @discardableResult
     static func transition(_: PMKNamespacer, with view: UIView, duration: TimeInterval, options: UIViewAnimationOptions = [], animations: (() -> Void)?) -> Guarantee<Bool> {
         return Guarantee { transition(with: view, duration: duration, options: options, animations: animations, completion: $0) }
     }
 
+    @discardableResult
     static func transition(_: PMKNamespacer, from: UIView, to: UIView, duration: TimeInterval, options: UIViewAnimationOptions = []) -> Guarantee<Bool> {
         return Guarantee { transition(from: from, to: to, duration: duration, options: options, completion: $0) }
-    }
-
-    static func perform(_: PMKNamespacer, animation: UISystemAnimation, on views: [UIView], options: UIViewAnimationOptions = [], animations: (() -> Void)?) -> Guarantee<Bool> {
-        return Guarantee { perform(animation, on: views, options: options, animations: animations, completion: $0) }
+    }
+
+    @discardableResult
+    static func perform(_: PMKNamespacer, animation: UISystemAnimation, on views: [UIView], options: UIViewAnimationOptions = [], animations: (() -> Void)?) -> Guarantee<Bool> {
+        return Guarantee { perform(animation, on: views, options: options, animations: animations, completion: $0) }
     }
 }