---input---
r"hello"
r"he\\llo"
r"hello\""
r"hello\\"
r"a*+?.|()\\^#"
r"a\"bc"
r""
r""i
r"hello"i
r"he\\llo"m
r"hello\""x
r"hello\\"s

---tokens---
'r'           Literal.String.Affix
'"'           Literal.String.Regex
'hello'       Literal.String.Regex
'"'           Literal.String.Regex
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'he\\\\llo'   Literal.String.Regex
'"'           Literal.String.Regex
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'hello\\"'    Literal.String.Regex
'"'           Literal.String.Regex
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'hello\\\\'   Literal.String.Regex
'"'           Literal.String.Regex
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'a*+?.|()\\\\^#' Literal.String.Regex
'"'           Literal.String.Regex
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'a\\"bc'      Literal.String.Regex
'"'           Literal.String.Regex
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'"'           Literal.String.Regex
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'"'           Literal.String.Regex
'i'           Literal.String.Affix
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'hello'       Literal.String.Regex
'"'           Literal.String.Regex
'i'           Literal.String.Affix
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'he\\\\llo'   Literal.String.Regex
'"'           Literal.String.Regex
'm'           Literal.String.Affix
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'hello\\"'    Literal.String.Regex
'"'           Literal.String.Regex
'x'           Literal.String.Affix
'\n'          Text.Whitespace

'r'           Literal.String.Affix
'"'           Literal.String.Regex
'hello\\\\'   Literal.String.Regex
'"'           Literal.String.Regex
's'           Literal.String.Affix
'\n'          Text.Whitespace
