--help shows required argument error and argument labels missing names

[stalep]

Issue 1: --help shows validation error for required arguments

When a command has a required @Argument and the user runs command --help, aesh validates the required argument before processing the --help flag, showing an error message above the help output:

$ jbang jdk install --help
Argument 'versionOrId' requires at least 1 value, but got 0.
Usage: jbang jdk install [<options>] <versionOrId> [<existingJdkPath>]
...

Expected: --help should bypass argument validation and show clean help output without errors. Exit code should be 0, not 2.

Issue 2: Help output shows generic "Argument:" instead of the paramLabel

The help output uses a bare Argument: header for each positional argument without showing its name/label:

Argument:
                  The version or id to install

Argument:
                  Pre installed JDK path

Expected: The argument name from paramLabel should be shown:

Argument:
  <versionOrId>   The version or id to install

Argument:
  <existingJdkPath>  Pre installed JDK path

The paramLabel is set on the @Argument annotation (e.g., @Argument(paramLabel = "versionOrId", ...)) and is correctly used in the synopsis line (<versionOrId>) but not in the Arguments section body.

Context

Found in jbang (jbangdev/jbang#2453). Picocli showed clean help on --help regardless of required arguments, and displayed argument names in the detailed section.

[stalep]

Fixed in commit a98b7ab. Two issues addressed:

1. --help bypasses required argument validation -- Both the arity check in AeshCommandLineParser.doParse() and the parser exception throw in DefaultCommandContainer.parseAndPopulate() now check hasOptionWithOverrideRequired() before reporting errors. When --help is set, validation errors are suppressed and help is shown cleanly with exit code 0.

2. Argument labels shown in help body -- Positional arguments (ARGUMENT/ARGUMENTS) now render their paramLabel or fieldName as <label> in the help output instead of bare whitespace. For example, <versionOrId> The version or id to install instead of just The version or id to install.