gh-149571: Make Element.itertext consistent for Comment and ProcessingInstruction

[hardiksingh5864]

This fixes a behavior mismatch between the pure-Python and C implementations of xml.etree.ElementTree.Element.itertext()
Added regression coverage in Lib/test/test_xml_etree.py

• Issue: Element.itertext() works differently in C and Python implementations #149571

[bedevere-app]

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[python-cla-bot]

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[StanFromIreland]

It seems you ran a linter, causing a massive diff. Please revert the unrelated changes.

[bedevere-app]

A Python core developer has requested some changes be made to your pull request before we can consider merging it. If you could please address their requests along with any other requests in other reviews from core developers that would be appreciated.

Once you have made the requested changes, please leave a comment on this pull request containing the phrase I have made the requested changes; please review again. I will then notify any core developers who have left a review that you're ready for them to take another look at this pull request.

[hardiksingh5864]

It seems you ran a linter, causing a massive diff. Please revert the unrelated changes.

It seems you ran a linter, causing a massive diff. Please revert the unrelated changes.

I have made the requested changes; please review again

[bedevere-app]

Thanks for making the requested changes!

@StanFromIreland: please review the changes made to this pull request.

[hardiksingh5864]

@StanFromIreland please review the changes made to this pull request.

[StanFromIreland]

Sorry I'm not an expert in these modules, I requested Serhiy.

[serhiy-storchaka]

Don't rush. First we need to decide which behavior is more desirable.

[hardiksingh5864]

Don't rush. First we need to decide which behavior is more desirable.

I’ll hold off on working on a fix until the expected behavior is clearer. Once confirmed about the desired behavior please share that to me as well