Not catching exclusive gateway with duplicate sequence flow values

[ghost]

If a model has an exclusive gateway with three sequence flows coming out of it, and two of them are checking for the same expression, then the linter should catch that and give a warning. So if the three values are:

• = return = 'A'
• = return = 'B'
• = return = 'A'

then a warning should display, as this would be a model that would not deploy successfully. The compiler would reject.