Fix typo in tracing docs
Fix typo in tracing docs


dtomcej/traefik,containous/traefik,FriggaHel/traefik,vdemeester/traefik,SantoDE/traefik,ldez/traefik,SantoDE/traefik,dtomcej/traefik,containous/traefik,vdemeester/traefik,ldez/traefik,dtomcej/traefik,mmatur/traefik,mmatur/traefik,ldez/traefik,SantoDE/traefik,FriggaHel/traefik,mmatur/traefik,vdemeester/traefik,vdemeester/traefik,SantoDE/traefik,dtomcej/traefik,FriggaHel/traefik,containous/traefik,FriggaHel/traefik,ldez/traefik,containous/traefik,mmatur/traefik