[desktop entry spec] new FullName key

[John Tapsell]

> Not sure what you mean with 'supporting GenericName', but the current
> GNOME HIG recommendations are the way they are precisely because of the
> translatability concerns of combining Name and GenericName
> programatically.

Could someone give an example where programmatically combining would
fail, if the combining was done as  i18n("%1 %2")  or even i18n("%1 -
%2")  ?