This is an extension of:
https://redgate.uservoice.com/forums/94413-sql-prompt/suggestions/6779217-add-n-to-unicode-type-literal-strings

Except I would like to improve this feature so that it is not limited to just variable declarations, but also for inline string literals.

For example, if an inline string literal contains a unicode character, it should have the N prefix. If anything it should probably be a Code Analysis rule rather than formatting because this change can absolutely impact code behavior. So I think it's better suited to be an analysis rule.