Update charted to 0.4.8 and roll

packages/petitparser/lib/src/lisp/name.dart

-part of petitparser.lisp;
-
-/// An unique symbolic name.
-class Name {
-
-  /// The interned symbols.
-  static final Map<String, Name> _interned = new HashMap();
-
-  /// Factory for new symbol cells.
-  factory Name(String name) {
-    return _interned.putIfAbsent(name, () => new Name._internal(name));
-  }
-
-  /// The name of the symbol.
-  final String _name;
-
-  /// Internal constructor for symbol.
-  Name._internal(this._name);
-
-  /// Returns the string representation of the symbolic name.
-  String toString() => _name;
-}