Table cells don't handle vertical direction properly

[xfq]

This issue is applicable to Chinese, Japanese, Korean, and Mongolian.

If you place the writing-mode property with a value of vertical-rl on an individual table cell, you would expect the text in that cell to be displayed vertically. This doesn't work as expected in all browsers: some don't apply vertical writing mode, or leave the text horizontal but rotate the CJK characters to the left.

For more details, see this GitHub issue, which is being used to track this gap. Please add any discussion there, and not to this issue.

[xfq]

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