Make find widget toggles configurable settings

[aybabtme]

Related to #4309 (comment)

Add to settings.json a way to always enable the case-sensitivity feature of Find.

[jrieken]

Setting? I believe that's stuff we should store and retrieve using the memento stuff...

[alexdima]

It would be the default value

[aybabtme]

@jrieken not sure what the memento stuff is. As a user, my expectations is that I'd be able to change that in my user settings (the JSON file) and then never have to think about it again.

[ramya-rao-a]

Find across files already persists the Find options (case sensitivity, whole word and regex). Find in a single file doesn't. Using configuration setting for default value for Find in File and keeping the existing persisting logic in Find across files will make experience inconsistent.

Can we not use the same persisting logic for Find in File instead of configuration setting?

[stefcameron]

I'd love to see a setting default for Alt+C (case-sensitive search and match). I'd like to be able to configure Code such that it defaults to case-sensitive search/match, and then be able to use Alt+C to toggle it on/off (but Alt+C should not change my default setting).

[rebornix]

Let's track the setting persistence in #6158