Include non-breaking prefixes file for source language

[kpu]

Currently bergamot-translator is just not loading non-breaking prefixes browsermt/bergamot-translator#104 . This is bad and should be fixed. I think the clean way to do this is to ship the file for the source language. They're small enough that some copying is probably ok.

[jerinphilip]

Can you bring the relevant nonbreaking_prefixes.xx into the archive, @XapaJIaMnu. I'll pick this up at BRT to include tests for browsermt/bergamot-translator#172.

[XapaJIaMnu]

Where exactly do we get those from? Is that part off ssplit, @ugermann ?

[kpu]

They come from moses. https://github.com/moses-smt/mosesdecoder/tree/master/scripts/share/nonbreaking_prefixes

[ugermann]

They actually ship with the sentence splitter and may diverge from Moses over time, as we add additional prefixes.