strong regex does not work correctly

[TheBlue-1]

This library formats strong values wrong in a certain edge case:

In slack:
*a*a* => *a*a*
*a*a* *a* => *a*a* a

The output of the library:
*a*a* => a*a
*a*a* *a* => a*a a

Note that this behaviour is correct for italic:
In slack:
_a_a_ => a_a
The output of the library:
_a_a_ => a_a

It would be very nice if you could adjust the regex to cover that edge case 🙃