Updater: fix typo in error message format string

Author: line0

modules/DependencyControl/Updater.moon

@@ -279,7 +279,7 @@ class UpdateTask extends UpdaterBase
 
         tmpDir = aegisub.decode_path "?temp/l0.#{DependencyControl.__name}_#{'%04X'\format math.random 0, 16^4-1}"
         res, dir = fileOps.mkdir tmpDir
-        return finish -30, "#{tmpDir} (#{err})" if res == nil
+        return finish -30, "#{tmpDir} (#{dir})" if res == nil
 
         @@logger\log msgs.performUpdate.updateReady, tmpDir