Inconsistent documentation with the behaviour of help command

[fmbenhassine]

Initially reported here: #1271 (comment) by @3ric-T.

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It seems that the documentation is not consistent with the behaviour of help command:

Typing <command> -h or <command> --help shows more information about a command, including the available parameters, their type, whether they are mandatory or not, and other details.

Currently, with either a built-in command or a new one, we have:

• with built-in commands

$>help --help
AVAILABLE COMMANDS

Built-In Commands
        script: Execute commands from a script file
        help: Display help about available commands
        quit, exit: Exit the shell
        version: Show version info
        clear: Clear the terminal screen

$>version --help
Version: 4.0.1

• with custom commands:

MyPrompt:> token --help

MyPrompt:> help token
NAME
        token - Display token information based on its name

SYNOPSIS
        token --tokenId String --help

OPTIONS
        --tokenId or -t String
        Token id, as defined in configuration
        [Optional, default = ]

        --help or -h
        help for token
        [Optional]

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