Update comments in the test

Co-authored-by: Chris Eibl <138194463+chris-eibl@users.noreply.github.com>

Author: sergey-miryanov

Lib/test/test_pyrepl/test_eventqueue.py

@@ -161,8 +161,8 @@ def _push(keys):
 
         self.assertIsInstance("ñ", str)
 
-        # we expect that no part of the multibyte string will remain in the
-        # internal buffer after an encode/decode error
+        # If an exception happens during push, the existing events must be
+        # preserved and we can continue to push.
         _push(b"b")
         with self.assertRaises(AssertionError):
             _push("ñ")