spec: clarify that identical structs must have identical field embeddings
The existing prose for struct identity did only require that two structs
"have the same sequence of fields, and if corresponding fields have the
same names, and identical types, and identical tags" for the structs to
be identical.
The implementation (forever) has also required that two corresponding
fields are either both embedded or not embedded. This is arguably part
of a struct's structure but is not explicitly specified.
This CL makes a minor change to the prose to address that.
Fixes #69472.
Change-Id: Ifa4ca69717986675642a09d03ce683ba8235efcb
Reviewed-on: https://go-review.googlesource.com/c/go/+/616697 Reviewed-by: Rob Pike <r@golang.org>
TryBot-Bypass: Robert Griesemer <gri@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>