string 'X slots left' wrong with WPML

[Valentina R]

Example: Site is using 2 langs with WPML. INventory of the product is 5. After booking one, the 'slots left' says '3 left', but it should say '4 left'.

But users are able to book 4 slots, like expected, so this part is fine. It's just the 'slots left' that is wrong.

Reported here: https://bizzthemes.com/forums/topic/order-one-unit-per-slot-get-two-units-per-slot/page/2/

And here: https://bizzthemes.com/forums/topic/product-stock-mismatch-when-translated/

[Željan Topić]

Fixed with 3.6.0