pathname: don't try to calculate symlink size.

Closes https://github.com/Homebrew/homebrew/issues/47532
Closes https://github.com/Homebrew/homebrew-dupes/issues/542

Library/Homebrew/extend/pathname.rb

@@ -30,7 +30,7 @@ module DiskUsageExtension
       @file_count = 0
       @disk_usage = 0
       self.find do |f|
-        if !f.directory? && f.basename.to_s != ".DS_Store"
+        if !f.directory? && !f.symlink? && f.basename.to_s != ".DS_Store"
           @file_count += 1
           @disk_usage += f.size
         end