Ignore keys with no valid KeyChar for vi movements

[thomazmoura]

PR Summary

Add a new function called ReadKeyChar that loops until a key with valid KeyChar is read. Change the calls for ReadKey().KeyChar on .vi.cs files so that vi movements have this new behaviour.

The idea is to fix issues on Windows like not being able to move to characters that are behind dead keys on layouts such as US-international (single quotes, for example, is input only after hitting single quote and then space). The current behavior on Windows breaks the chain by returning a PSKeyInfo without a valid KeyChar and then trying to move to it (instead of waiting for the next key press to get the actual input).

PR Checklist

• [ X ] PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• [ X ] Summarized changes
• Make sure you've added one or more new tests
• [ X ] 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:

I'm not really sure how to unit test it since it seems dependent on the keyboard layout, but I welcome suggestions.

So far I've manually tested it on Windows running PowerShell 7.4.1 with Windows Terminal, conhost and Visual Studio Code and Linux (WSL2) with Windows Terminal.

The only caveaut I've found so far is that function keys (such as F1~F12) will also be ignored, But since the only code that is being changed to use the new version are the vi movement ones I believe this is not an issue.

Microsoft Reviewers: Open in CodeFlow

[thomazmoura]

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