Improve replacement between tokens

[Johnsoct]

• SRP
• Open/Closed (open for extension, closed for modification)
• Liskov Substitution (Subtypes should be substitutable for their base types)
• Interface Segragation (Client should not be forced to depend on interfaces it doesn't use)
• Dependency Inversion (high-level modules should not depend on low-level modules, but both should depend on abstractions (middleman)

[Johnsoct]

I don't really love that the regex's are hardcoded as the key, and the submatch regex is an identical piece of the regex, but for right now, I think it's fine to leave it simple vs further abstracted.