HtmlFormatter - Embed context and extra datas in tables

Hello,

In fact, I first wanted to extend HtmlFormatter to override public function format (cause json is not easy-to-read, especially with Exception traces).
But addRow and addTitle are private.

If my PR is rejected, is it possible to move them to protected ?

Thanks
I want to embed a table element in the 2nd td of both Context and Extra rows, to improve readibility. So table element must not be escaped.
Btw, each Context / Extra row is alreay esacped by $embeddedTable .= $this->addRow($key, $this->convertToString($value));