fix(plural/fr): fix french plural

The difference is l.296 (the trailing whitespace trimming renders this unreadable…):
```diff
-  "plurals": function(n) { return Number(n > 1); }
+  "plurals": function(n) { return Math.abs(n) >= 2; }
```

This is self-explainable. French plural rules were just wrong. :)
wouldn't it make sense to apply Math.abs here -> so floats work in other languages too?