Add argument selection handler to sample profile

[ThePSAdmin]

PR Summary

This adds a handler to the sample PSReadLine profile which cycles through the arguments on the current command line, and selects the entire argument. This makes it simpler to quickly change an argument when recalling a command from the history, or changing the values of an argument when using a suggested command from a PSReadLine predictor plugin.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Make sure you've added one or more new tests
• Make sure you've tested these changes in terminals that PowerShell is commonly used in (i.e. conhost.exe, Windows Terminal, Visual Studio Code Integrated Terminal, etc.)
• User-facing changes
  • Not Applicable
  • OR
  • Documentation needed at PowerShell-Docs
    • Doc Issue filed:

Microsoft Reviewers: Open in CodeFlow

[ghost]

All CLA requirements met.

[lzybkr]

Looks pretty good. Formatting should be consistent with the rest of the file, e.g. use 4 spaces for indent.

[daxian-dbw]

Very interesting! The Az predictor team is actually looking for a similar experience, and we may have a built-in function in future.

[daxian-dbw]

Looks good. I left 2 minor comments, once you address them we can merge the PR.

[daxian-dbw]

@lzybkr Could you take another look?

[lzybkr]

If there are no arguments, the cursor shouldn't move. An early return (and a Ding?) also avoids other potential issues, like indexing out of bounds (which is reported in V2 strict mode.)

I have conflicting feelings about not selecting arguments, but this is a sample, so I don't care if that behavior is changed. I say conflicting because I tried this one a command line like:

echoargs -a 1 --long 2

Repeatedly pressing Alt+a would select 1, --long, and 2. In this example, it's surprising that -a is not selected but --long is. I know why, but it does feel weird.

[lzybkr]

Suggested change

	if ($asts.Count -eq 0) {
	[Microsoft.PowerShell.PSConsoleReadLine]::Ding()
	return
	}

[ghost]

🎉 v2.2.0-beta2 has been released which incorporates this pull request. 🎉