bpo-34160: Preserves order of minidom of Element attributes

[dfrojas]

This PR is a continuation of the work in #10163

https://bugs.python.org/issue34160

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[vstinner]

This change has already been committed: commit 3b05ad7, PR #10190.

[dfrojas]

You are right, I did not realize that @serhiy-storchaka have made that changes some minutes before this PR.

[vstinner]

Suggested change

	for a_name in a_names:
	for a_name in attrs.keys():

[vstinner]

No, please don't document private functions.

[dfrojas]

@vstinner @serhiy-storchaka I had conflicts doing the changes, the PR has commits from other developers. It's better if I close this PR and open a new one?

[serhiy-storchaka]

Something wrong happen when you synchronized your branch with master. Did you run git merge master? If there are conflicts, it is better to resolve them and continue in the same PR.

[taleinat]

@dfrojas, I recommend:

1. Create a new branch from the current master branch.
2. Cherry-pick your relevant commits one by one in chronological order.
3. Review the changes, run the tests etc.
4. If everything looks okay, force-push the new branch into the branch for this PR, e.g. on the new branch: git push -f origin [bpo-34160](https://bugs.python.org/issue34160)-10163PR-continuation

[dfrojas]

@serhiy-storchaka Do I have to write a NEWS specifically for minidom? Or with the NEWS in this PR is enough?

[taleinat]

@serhiy-storchaka Do I have to write a NEWS specifically for minidom? Or with the NEWS in this PR is enough?

Perhaps just update the NEWS entry you referenced and add "minidom" after "ElementTree".

[serhiy-storchaka]

Either add a new news entry, or update an existing entry added for #10219. The rest LGTM.