Fix reading time on mixed CJK/non-CJK text. Fixes #10031

[DeinAlptraum]

Fixes the reading time for mixed texts, by computing separete word counts for CJK and non-CJK texts, then computing their reading times separately via the two formulas, and finally summing them up.

Imo this also makes the hasCJKLanguage setting useless for readingTime, please do correct me if I'm wrong here.

[CLAassistant]

All committers have signed the CLA.

[github-actions[bot]]

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[DeinAlptraum]

Yes, I believe it fits the description, including closing an open issue.