Remove dead code: unused ENCODING constant and Python 2 next() shim

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: derek73

nameparser/parser.py

@@ -11,9 +11,6 @@
 from nameparser.config import Constants
 from nameparser.config import DEFAULT_ENCODING
 
-ENCODING = 'utf-8'
-
-
 def group_contiguous_integers(data: Iterable[int]) -> list[tuple[int, int]]:
     """
     return list of tuples containing first and last index
@@ -159,9 +156,6 @@ def __setitem__(self, key: str, value: str) -> None:
         else:
             raise KeyError("Not a valid HumanName attribute", key)
 
-    def next(self) -> str:
-        return self.__next__()
-
     def __next__(self) -> str:
         if self._count >= len(self._members):
             self._count = 0