Update reference.md
Update reference.md

Github rendering bug on markdown title
nyaruka/django-hamlpy,jessemiller/HamlPy,GetHappie/HamlPy,Psycojoker/HamlPy,frankvdp/HamlPy,GetHappie/HamlPy,GetHappie/HamlPy,GetHappie/HamlPy,Psycojoker/HamlPy,frankvdp/HamlPy,Psycojoker/HamlPy,nyaruka/django-hamlpy,jessemiller/HamlPy,frankvdp/HamlPy,jessemiller/HamlPy,frankvdp/HamlPy