added user facing error description for some cases in YouTubeKitError

Sources/YouTubeKit/Errors.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-public enum YouTubeKitError: Error {
+public enum YouTubeKitError: String, Error {
     case maxRetriesExceeded
     case htmlParseError
     case extractError
@@ -20,3 +20,28 @@ public enum YouTubeKitError: Error {
     case membersOnly
     case videoRegionBlocked
 }
+
+extension YouTubeKitError: LocalizedError {
+
+    public var errorDescription: String? {
+        switch self {
+        case .videoUnavailable:
+            return NSLocalizedString("Video unavailable", comment: "")
+
+        case .videoAgeRestricted:
+            return NSLocalizedString("Video age restricted", comment: "")
+
+        case .liveStreamError:
+            return NSLocalizedString("Can't extract video from livestream", comment: "")
+
+        case .videoPrivate:
+            return NSLocalizedString("Video is private", comment: "")
+
+        case .membersOnly:
+            return NSLocalizedString("Video is members only", comment: "")
+
+        default: return nil
+        }
+    }
+
+}