Issue #29145: Merge 3.6.
diff --git a/Objects/stringlib/transmogrify.h b/Objects/stringlib/transmogrify.h
index a314572..326ce14 100644
--- a/Objects/stringlib/transmogrify.h
+++ b/Objects/stringlib/transmogrify.h
@@ -261,7 +261,7 @@
     assert(count > 0);
     if (to_len > (PY_SSIZE_T_MAX - self_len) / count) {
         PyErr_SetString(PyExc_OverflowError,
-                        "replace bytes are too long");
+                        "replace bytes is too long");
         return NULL;
     }
     result_len = count * to_len + self_len;