CorrectionExtent should support .ToString()

[StartAutomating]

Summary of the new feature

Script Analyzer rule connections use the default ToString(), which merely displays the type.

This means that to test the result of a script analyzer rule with a regex, one needs to dig into subproperties.

It also means that, say, a list of corrections in a CSV will simply look broken.

Proposed technical implementation details (optional)

[Microsoft.Windows.PowerShell.ScriptAnalyzer.Generic.CorrectionExtent] should override .ToString() method to output the correction string.