Update fontbakery-check-ttf.py
Update fontbakery-check-ttf.py

Document the OS/2 table weightclass !< 250 rule
graphicore/fontbakery,googlefonts/fontbakery,graphicore/fontbakery,moyogo/fontbakery,moyogo/fontbakery,googlefonts/fontbakery,googlefonts/fontbakery,graphicore/fontbakery,moyogo/fontbakery