Remove the --fix parameter from dart format, this is no longer supported.

Author: renggli

bin/generate_bindings.dart

@@ -184,7 +184,7 @@ class Type {
 
 /// Pretty prints and cleans up a Dart file.
 Future<void> format(File file) async =>
-    Process.run('dart', ['format', '--fix', file.absolute.path]);
+    Process.run('dart', ['format', file.absolute.path]);
 
 void generateWarning(StringSink out) {
   out.writeln('// AUTO-GENERATED CODE: DO NOT EDIT');