📝 add more doc for CLI help string

src/delarte/cli.py

@@ -1,6 +1,13 @@
 # Licence: GNU AGPL v3: http://www.gnu.org/licenses/
 # This file is part of [`delarte`](https://git.afpy.org/fcode/delarte.git)"""CLI arguments related module."""
 
+"""
+usage: delarte [-h|--help]                         - print this message
+or: delarte program_page_url                       - show available versions
+or: delarte program_page_url version               - show available video resolutions
+or: delarte program_page_url version resolution    - download the given video
+"""
+
 import argparse
 
 
@@ -11,6 +18,8 @@ class Parser(argparse.ArgumentParser):
         """Generate a parser."""
         super().__init__(
             description="downloads Arte's videos with subtitles",
+            epilog=__doc__,
+            formatter_class=argparse.RawDescriptionHelpFormatter,
         )
         self.add_argument(
             "url",