texlive.md: texinfo pdf compilation with texi2pdf

[giuliods]

I made a mess before with some pulls, this is the last one

When texinfo is used to generate a pdf file it uses TeX with a macro file called texinfo.tex. As written on https://www.gnu.org/software/texinfo/manual/texinfo/texinfo.html#First-Line:

These are in a file called texinfo.tex, which should have been installed on your system along with either the TeX or Texinfo software

Which doesn't happen here. The resolution is simple and only require to install texinfo with tlmgr.

I added a small paragraph explaining the problem, a short solution and a link with more details.