Add support to show suggestions on CommandNotFound exception

[SteveL-MSFT]

PR Summary

Add -UseFuzzyMatching switch to Get-Command to return commands that fuzzy match to the name in order of closest match to least. Integrate this with the suggestion framework so that on a CommandNotFound exception, suggestions are shown for likely commands the user intended. The suggestions are part of the console host and write directly to the console so don't see a way to test that. In the future, we should consider changing that to using information stream.

PR Checklist

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• Change is not breaking
• Make sure all .h, .cpp, .cs, .ps1 and .psm1 files have the correct copyright header
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.
• User-facing changes
  • Not Applicable
  • OR
  • User-facing Doc -UseFuzzyMatching switch added to Get-Command MicrosoftDocs/PowerShell-Docs#3429
    • Issue filed - Issue link:
• Testing - New and feature
  • Not Applicable or can only be tested interactively
  • OR
  • Make sure you've added a new test if existing tests do not effectively test the code changed
    • Add [feature] if the change is significant or affects feature tests

[iSazonov]

We could consider other names of the parameter: -Fuzzy, -FuzzyMatching, -ShowSuggestions, -Suggestions.

We need PowerShell Committee approvement for the new public API.

[rjmholt]

We could introduce a test hook to do something like write output to the information stream or to a variable for testing purposes for now

[SteveL-MSFT]

@rjmholt I suggest we defer the test hook as that would make sense for testing suggestions in general and not this specific change.

[iSazonov]

It was good to have a tracking issue if we needed these special tests.

[SteveL-MSFT]

@iSazonov created #8486

[TravisEz13]

@SteveL-MSFT Do you want to wait on Rob to review your changes?

[SteveL-MSFT]

@TravisEz13 if @rjmholt has further comments, we can treat it as a separate issue and PR. Would like to get this in for next Preview

[iSazonov]

It would be good to fix some style issues and "s_" before merge.

[SteveL-MSFT]

@PowerShell/powershell-committee reviewed this and is ok with -UseFuzzyMatching