When editing a table where some columns are left/center/right aligned, currently a newly created row does not obtain any of this alignment. Let's copy it from the row cells above.
We want to support the following variants:
<td align="right"></td> <td style="text-align: right"></td> <tr align="right"></tr> <tr style="text-align: right"></tr> <td valign="top"></td> <td style="vertical-align: top"></td> <tr valign="top"></tr> <tr style="vertical-align: top"></tr>
Note: align and valign are deprecated DOM attributes, but still widely used in Wikipedia articles.