update Term Suggester, test multiple completion suggestions

[p365labs]

In reference #1541 I made some more tests, I also addedd a method for choosing the distance algorithm

[p365labs]

This PR in fact add a test in order to verify the #1541 to have a use case that cover that example.
I've also added a method

public function setStringDistanceAlgorithm($distanceAlgorithm)

and its test to include this option which was not in the class.

[ruflin]

Code LGTM. Want to add a changelog entry?

[p365labs]

@ruflin done :)