Control over Help Text Headers

When (and only when) the help text is shown, it adds the application name, version, and copyright info before writing the options details. However, I'd either like to include with every run, or exclude it completely so I can output my own info. However, I can't figure out how to do that.

I'm just using the default ParseArguments/MapResult code:

`
return Parser.Default.ParseArguments(args)
.MapResult(
(AddOptions opts) => RunAddAndReturnExitCode(opts),
(CommitOptions opts) => RunCommitAndReturnExitCode(opts),
(CloneOptions opts) => RunCloneAndReturnExitCode(opts),
errs => 1);
`

Start with the Parser.Default.ParseArguments and MapResult entry points shown in the issue, then trace how help text is produced. The work is complete when callers can consistently include the application header on every run or omit it entirely, with behavior matching the requested choice.

Escrita pelo modelo de indexação a partir do texto da issue.