Unicode characters do not appear in PDF

[DavidLeoni]

Unicode characters such as ✪ don't display in PDFs

To fix it, tried to add this in conf.py without success:
Taken inspiration from this

#: To fix @ issue, copied from here: https://github.com/sphinx-doc/sphinx/issues/4136#issuecomment-335956163
latex_engine = 'xelatex'
latex_elements = {
    'papersize': 'a4paper',    
    'preamble' : r"""\usepackage[T1]{fontenc} 
\usepackage[utf8]{inputenc}
"""
}