Fix the API_AVAILABLE syntax for enum

Author: dreampiggy

SDWebImageLinkPlugin/Classes/SDWebImageLinkError.h

@@ -14,8 +14,7 @@
 
 FOUNDATION_EXPORT NSErrorDomain const SDWebImageLinkErrorDomain API_AVAILABLE(macos(10.15), ios(13.0), watchos(6.0));
 
-API_AVAILABLE(macos(10.15), ios(13.0), watchos(6.0))
 typedef NS_ERROR_ENUM(SDWebImageLinkErrorDomain, SDWebImageLinkError) {
     /// Metadata have no any ImageProvider or IconProvider to query
     SDWebImageLinkErrorNoImageProvider = 10000,
-};
+} API_AVAILABLE(macos(10.15), ios(13.0), watchos(6.0));