Document XeLaTeX usage

[jpgoldberg]

It is not clear from the documentation whether this package will work with XeLaTeX. And if it does work with XeLaTeX whether there are any specific instructions for it. If this is pdfTeX and luaTeX only, please make that more clear.

[jpgoldberg]

I see from the tagpdf documentation that

The package [tagpdf] works currently with pdflatex and lualatex. First steps have been done to also enable support for xelatex and the latex-dvips-route; but this isn’t yet much tested.

It would be useful to include that in the axessibility documentation.

[maiettada]

Hello @jpgoldberg, your suggestion is very much appreciated. We'll make the necessary additions in the documentations