refactor "substitute copyright, registered and trademark...
refactor "substitute copyright, registered and trademark...

... symbols" check. (issue #978)

graphicore/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,graphicore/fontbakery,googlefonts/fontbakery,googlefonts/fontbakery,moyogo/fontbakery,graphicore/fontbakery,moyogo/fontbakery