Improve grammar of exceptions

[xPaw]

I've noticed the value printed in ThrowArgumentParseFailed may not be correct in some cases, like when TryIncrementIndex fails, it will print the argument name itself, rather than the value (because there isn't one). Maybe this should be special cased to a new exception like Argument '{argumentName}' requires a value, but none was specified.?

[neuecc]

Thanks!
I agree, while the current solution was a bit of a quick fix, it would be preferable to have a more thorough separation.