[PATCH v6 0/9] MR538: mshtml: Implement more methods for Elements.

[Gabriel Ivăncescu (＠insn)]

`getAttributeNS` is tested with the `setAttributeNS` implementation.

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  v6: mshtml: Implement HTMLTitleElement's text property.
      mshtml: Implement childElementCount for Elements.
      mshtml: Implement previousElementSibling for Elements.
      mshtml: Implement nextElementSibling for Elements.
      mshtml: Implement lastElementChild for Elements.
      mshtml: Implement hasAttributeNS for Elements.
      mshtml: Implement removeAttributeNS for Elements.
      mshtml: Implement setAttributeNS for Elements.
      mshtml: Implement getAttributeNS for Elements.

https://gitlab.winehq.org/wine/wine/-/merge_requests/538