tr, tbody, thead and tfoot pass none of their properties to their cells #542

Part of #520 (step 21).

Measured on gravitypdf at d660a410, PHP 8.5.4. color, font-size, font-family, font-weight, font-style, letter-spacing, word-spacing, text-transform, text-shadow, text-align and line-height, set on a tr, tbody or thead by a rule or style="", all fail to reach the text of its cells. Only the table passes properties to cells, through base_table_properties. Row backgrounds do work.

Fix. Pass a row's and a row group's inherited properties to their cells, over the table's and under the cell's own.

This changes output wherever a document styles rows, which today has no effect on the text of the cells. Say so in the PR.

Tests. Each property from each of tr, tbody, thead and tfoot, and a rule on the cell still winning.