plot readable --help

by default argparse ignores paragraph ends and lists, making especially the lists pretty unreadable. RawDescriptionHelpFormatter does not format description texts. It does not look good but is a lot better readable.
cantools · eerimoq · Jan 4, 2021 · Dec 21, 2020 · Dec 22, 2020 · Dec 22, 2020
commit 527018dfb116ead0a928e7400c925ceb7aa9d2bc
diff --git a/cantools/subparsers/plot.py b/cantools/subparsers/plot.py
@@ -46,6 +46,7 @@
 import binascii
 import struct
 import datetime
+import argparse
 from argparse_addons import Integer
 from matplotlib import pyplot as plt
 
@@ -498,7 +499,8 @@ def add_subparser(subparsers):
     '''
     decode_parser = subparsers.add_parser(
         'plot',
-        description=__doc__)
+        description=__doc__,
+        formatter_class=argparse.RawDescriptionHelpFormatter)
     decode_parser.add_argument(
         '-c', '--no-decode-choices',
         action='store_true',