Fixed horizontal alignment of table cell in RTL content.

[niegowski]

Suggested merge commit message (convention)

Fix: Horizontal alignment of table cell in RTL content. Closes ckeditor/ckeditor5#6371.

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Additional information

Justify icon looks odd for RTL languages - probably should be mirrored?

[coveralls]

Coverage increased (+0.0001%) to 99.935% when pulling 956eb3e on i/6371 into b905aa5 on master.

[Reinmar]

I tested this manually and I can't see a difference with master. But perhaps I'm not getting what the issue was. Or there's still something wrong. E.g., shouldn't table cells be right aligned (also visually – in the editor) in a newly created cells. In fact, it's also left aligned in the entire editor:

I think that the RTL sample should look more like this:

So it seems that there's something else wrong with the table's RTL manual test itself. Am I right, @oleq?

[niegowski]

@Reinmar it's because content language in manual test for RTL is set to 'en' - https://github.com/ckeditor/ckeditor5-table/blob/master/tests/manual/rtl.js#L19

[oleq]

...which looks like a forgotten change made for some development purpose. @panr?

[panr]

...which looks like a forgotten change made for some development purpose. @panr?

If ui: ar should always correspond with content: ar, then yes, it's a bug here.