Fix YAML syntax error in workflow file

- Remove unescaped single quote in Perl script comment

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Co-Authored-By: Claude <noreply@anthropic.com>

Author: zeha

.github/workflows/validate-masterlist.yml

@@ -53,7 +53,7 @@ jobs:
             $has_site = $has_type = $has_country = 0;
           }
           END { 
-            # Check last entry if file doesn'\''t end with blank line
+            # Check last entry if file does not end with blank line
             if ($has_site && !$has_type) {
               print "ERROR: Entry $entry ($site) missing Type field\n";
               $errors++;