Minor: Improve docstring on asset_by_name()
Minor: Improve docstring on asset_by_name()

googlefonts/fontbakery,vitalyvolkov/fontbakery,vitalyvolkov/fontbakery,jessamynsmith/fontbakery,davelab6/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,graphicore/fontbakery,moyogo/fontbakery,googlefonts/fontbakery,graphicore/fontbakery,vitalyvolkov/fontbakery,moyogo/fontbakery,moyogo/fontbakery