Revert "[bugfix] site.lang is different from site.code"
Revert "[bugfix] site.lang is different from site.code"

This reverts commit d9a0c49c4a73e08b2df30c680d250d8f8fdd9d9a.

Bug: T228322
Change-Id: Ic8a1a7b580dff8471dbb5cfb844dc9e329297373

PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core,wikimedia/pywikibot-core