fix: set displayName to PBXFileSystemSynchronizedBuildFileExceptionSet

ref: CocoaPods#1000

Author: paul-han-n

lib/xcodeproj/project/object/file_system_synchronized_exception_set.rb

@@ -35,7 +35,7 @@ class PBXFileSystemSynchronizedBuildFileExceptionSet < AbstractObject
         attribute :platform_filters_by_relative_path, Hash
 
         def display_name
-          "Exceptions for \"#{GroupableHelper.parent(self).display_name}\" folder in \"#{target.name}\" target"
+          'PBXFileSystemSynchronizedBuildFileExceptionSet'
         end
       end
 
@@ -54,7 +54,7 @@ class PBXFileSystemSynchronizedGroupBuildPhaseMembershipExceptionSet < AbstractO
         attribute :platform_filters_by_relative_path, Hash
 
         def display_name
-          "Exceptions for \"#{GroupableHelper.parent(self).display_name}\" folder in \"#{build_phase.name}\" build phase"
+          'PBXFileSystemSynchronizedBuildFileExceptionSet'
         end
       end
     end