Add render as HTML function to Excel Attachments

Since upgrading to Confluence 6.12.X we can no longer 'Edit document' when it comes to an attached Excel file (which then gets rendered in HTML and is searchable).

We have to re-add the attachment, after which it is added as a thumbnail, or a link. This can then be edited using the Companion, but it doesn't render as HTML before hand in Confluence, so we you cannot use CTRL+F to search through it. Beyond that, the thumbnail is tiny (and pixelated when forced to be bigger).

It'd be great if the excel file would simply be rendered, then we'd have no problem, but right now we are dependent on the old 'excel macro' add-on (which is planned to be phased out) in order for it to render appropriately, however the 'Edit document' link is then missing as referenced in the ticket below:

CONFSERVER-56334

Perhaps a solution would be to add this additional functionality to the preview popup so it displays as below and some of the original functionality would be restored.