Fix replace()/replace!() for ChainedVector when supplying count

[laborg]

Fix #112

Not sure if this is the fastest implementation, but now it does what I would have expected from it and is in line with the behaviour of replace/replace! on an ordinary Array

[ararslan]

Implementation looks good I think, but it'd be nice to have tests for replace (currently they're only for replace!), for the error thrown when count < 0, and for the behavior when count == 0.

[ararslan]

Suggested change

continue

The continue has no effect here; there's nothing else in the loop body that appears after it so the loop will continue regardless.

[ararslan]

Suggested change

continue

(Same comment as in the other function)

[ararslan]

Is there any reason you opted not to implement replace in terms of replace!, as is done for the Base methods? It would be worth looking at the Base methods' implementations, as those account for a number of things not accounted for here at the moment, e.g. handling missing in comparisons.

[laborg]

Replaced by #118