Tweaking lib/symbols for XML entities

[Pavel Sanda]

On Mon, Jun 15, 2020 at 08:43:39AM +0200, Kornel Benko wrote:
> Thanks, no warnings.
> 
> My try to export was not successful though.
> 	Error: Couldn't export file
> 	----------------------------------------
> 	No information for exporting the format MS Excel Office Open XML.

These patches are aimed at docbook (to be completed in future) not for MS Excel Office Open XML export.

Pavel