The namespace defined by xmlns="value" can be overridden in every included tag
by the empty namespace xmlns="" without a prefix.
Method to calculate indent of XML handles depth of tag and its associated namespace is
still active even when no indent is required.
An XMLName field in a struct means that namespace must be enforced even if empty.
This occurs only on an inner tag as an override of any non-empty namespace of its outer tag.
An attribute is added to have the required namespace display.
Fixes #7113
Change-Id: I57f2308e98c66f04108ab136d350bdc3a6091e98
Reviewed-on: https://go-review.googlesource.com/c/go/+/108796
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com> Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>