Offer Result based functions for Fluent

[TiemenSch]

Currently, the FluentLanguageLoader offers error logging functionality, but no actual Results. Would you consider adding try_... methods that return a Result with distinct errors?

These could contain Error types that have a Display implementation that is equivalent to the current messages, such that the current methods can wrap around their try_ counterparts in a compact way.

This might be a design decision which I'm not aware of, but I just wanted to put it out there.

[kellpossible]

seems like a good idea, I'm open to contributions!