Dart format with latest SDK (#81)

diff --git a/lib/src/shell_words.dart b/lib/src/shell_words.dart
index d293e39..bfba529 100644
--- a/lib/src/shell_words.dart
+++ b/lib/src/shell_words.dart
@@ -91,7 +91,9 @@
                 next == $backslash) {
               token.writeCharCode(next);
             } else {
-              token..writeCharCode($backslash)..writeCharCode(next);
+              token
+                ..writeCharCode($backslash)
+                ..writeCharCode(next);
             }
           } else {
             token.writeCharCode(scanner.readChar());