🐛 Bug Fix
- Table: deleting a row could throw
NotFoundError: Failed to execute 'insertBefore' on 'Node'for tables with mixed rowspans (e.g. after inserting a column and repeatedly splitting/merging cells). When a row with a rowspan cell was removed, the cell was moved into the next row and inserted before the cell that logically follows it — but that reference cell can physically belong to an earlier<tr>(when it spans down from a row above), which is not a child of the target row.__removeRownow picks the first following cell that actually belongs to the next row (falling back toappendChild). Fixes #1358.