Fix 'deecorator' typo in test/test_dataclasses (GH-5899)

(cherry picked from commit 973cae07d6ce7f5a93bd9cd3bcb724a96cfe14e9)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>
diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py
index 9752f55..c24af7f 100755
--- a/Lib/test/test_dataclasses.py
+++ b/Lib/test/test_dataclasses.py
@@ -2403,7 +2403,7 @@
                 return 301
 
         # If frozen or eq is None, then use the default value (do not
-        # specify any value in the deecorator).
+        # specify any value in the decorator).
         for frozen, eq,    base,   expected       in [
             (None,  None,  object, 'unhashable'),
             (None,  None,  Base,   'unhashable'),