gh-106242: Make ntpath.realpath errors consistent with abspath when there are embedded nulls (GH-108248)

* gh-106242: Make ntpath.realpath errors consistent with abspath when there are embedded nulls

* Update 2023-08-22-00-36-57.gh-issue-106242.q24ITw.rst

mention Windows and the former incorrect ValueError.

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Co-authored-by: Gregory P. Smith <greg@krypto.org>