Trigraph/digraph sequences are not supported

[dsamarin]

Tokenizer.prototype.nextch should recognize trigraph sequences and instead return the correct replacement.

Before any other processing takes place, each occurrence of one of the following
sequences of three characters (called trigraph sequences12)) is replaced with the
corresponding single character.

??=  #
??(   [
??/   \
??)   ]
??'   ^
??<   {
??!   |
??>   }
??-   ~

Digraphs are easier to add since the punctuators are constructed automatically as a trie structure and can be added with the add() method of Token.punctuators.