Use gh bug nubmer

Author: matthieucan

Lib/test/test_email/test__header_value_parser.py

@@ -2983,7 +2983,7 @@ def mime_parameters_as_value(self,
             [('r', '"')],
             [errors.InvalidHeaderDefect]*2),
 
-        # bpo-42946: Unicode super-script digits (and others) are not allowed
+        # gh-87112: Unicode super-script digits (and others) are not allowed
         # as section numbers.
         'non_allowed_digits': (
             'foo*0=bar; foo*²=baz',