[Sane-analysis] Update to wiki page on pion production

[O. A. Rondon]

In advance of tomorrow's analysis meeting, I have updated my wiki page
with results and plots of my uncertainty weighted fits to the Yerevan
charged pion photoproduction data, which include estimated uncertainties
coming from statistics, systematics, and data digitization.

I also have fitted the cross section for neutral pions, using the
weighted average of the charged pion ones. I was using the simple
average before now, in the absence of uncertainties.

Finally, I've run epc with the new weighted fit to negative pions on C,
to get the corresponding electroproduction cross section at 5 GeV and 13
deg., to compare with the DESY data.

The updates are indicated by *NEW* labels here:
https://hallcweb.jlab.org/experiments/sane/wiki/index.php/Inclusive_pion_and_nucleon_electroproduction

I will later include more details of the procedure used to estimate the
errors.

Cheers,

Oscar