tooltipHtml for collapsibleTreeSummary? #70
Description
collapsibleTreeSummary utilizes the hierarchy to define the hierarchy, while collapsibleTreeNetwork requires the hierarchy to be encoded in 2 parent-child columns (or a data.tree for collapsibleTree(tooltipHtml='')), so the interface is quite different, but only collapsibleTreeNetwork includes tooltipHtml. It would be helpful to include tooltipHtml for collapsibleTreeSummary.
In regards to using collapsibleTree(tooltipHtml='') with a data.tree object, it would be helpful to get an example, since it is not clear how to include the html column, given that just specifying the html-defining column (e.g., 'html_column') in collapsibleTree(data.tree_object, tooltipHtml='html_column') results in the error: tooltipHtml column name is incorrect