Issue #29145: Merge 3.6.

diff --cc Objects/stringlib/transmogrify.h
index a314572a72ba49d0c8255eeada553720a605faab,a314572a72ba49d0c8255eeada553720a605faab..326ce14849c9826547c594370fc641d0ee6db203
--- 1/Objects/stringlib/transmogrify.h
--- 2/Objects/stringlib/transmogrify.h
+++ b/Objects/stringlib/transmogrify.h
@@@ -261,7 -261,7 +261,7 @@@ stringlib_replace_interleave(PyObject *
      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;

diff --cc Objects/unicodeobject.c
Simple merge