Add a style for %(prog)s in the usage

[hamdanal]

Closes #55

Add a new style for %(prog)s in the usage. The style is applied in argparse-generated usage and in user defined usage whether the user usage is plain text or rich markup.

Click to see the code

import argparse

from rich import get_console

from rich_argparse import RichHelpFormatter

console = get_console()


console.rule("Auto generated usage")
parser = argparse.ArgumentParser(
    prog="connect",
    description="Edit or show the location of the user configuration file.",
    formatter_class=RichHelpFormatter,
)
parser.print_usage()


console.rule("User defined plain text usage")
parser = argparse.ArgumentParser(
    prog="connect",
    description="Edit or show the location of the user configuration file.",
    usage="%(prog)s [-h] config_name\n       %(prog)s [-h] url [user] [password]",
    formatter_class=RichHelpFormatter,
)
parser.print_usage()


console.rule("User defined markup usage")
RichHelpFormatter.usage_markup = True
parser = argparse.ArgumentParser(
    prog="connect",
    description="Edit or show the location of the user configuration file.",
    usage="[u]%(prog)s \\[-h] config_name[/]\n       [i]%(prog)s \\[-h] url \\[user] \\[password][/]",
    formatter_class=RichHelpFormatter,
)
parser.print_usage()