Remove qu2cu.cli from --help

Lib/fontTools/qu2cu/__main__.py

@@ -1,6 +1,6 @@
 import sys
 
-from .cli import main
+from .cli import _main as main
 
 
 if __name__ == "__main__":

Lib/fontTools/qu2cu/cli.py

@@ -42,7 +42,7 @@ def _font_to_cubic(input_path, output_path=None, **kwargs):
     font.save(output_path)
 
 
-def main(args=None):
+def _main(args=None):
     """Convert an OpenType font from quadratic to cubic curves"""
     parser = argparse.ArgumentParser(prog="qu2cu")
     parser.add_argument("--version", action="version", version=fontTools.__version__)