---input---
f"{fn(lst,2)} {fn(lst,3)}"

---tokens---
'f'           Literal.String.Affix
'"'           Literal.String.Double
'{'           Literal.String.Interpol
'fn'          Name
'('           Punctuation
'lst'         Name
','           Punctuation
'2'           Literal.Number.Integer
')'           Punctuation
'}'           Literal.String.Interpol
' '           Literal.String.Double
'{'           Literal.String.Interpol
'fn'          Name
'('           Punctuation
'lst'         Name
','           Punctuation
'3'           Literal.Number.Integer
')'           Punctuation
'}'           Literal.String.Interpol
'"'           Literal.String.Double
'\n'          Text.Whitespace
