Make PSReadLine default on Windows

[TylerLeonhardt]

PR Summary

Make PSReadLine default on Windows because:

1. people don't remember do add it
2. we need more feedback

PR Checklist

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[rkeithhill]

I think having this feature on by default is the way to go. However, will we have a way to "disable" the feature if necessary? I know I've run into the endless prompt loop issue enough that I disabled the feature.

[TylerLeonhardt]

@rkeithhill yeah you would just do:

powershell.developer.featureFlags: []

[Jaykul]

You added PRSL and didn't make it the default? 👀