Market "Sell..." button: add spaces, remove bracket

Fix some text appearance issues:

- Use item.text instead of item.key so that users see "Tiger Cub" rather than "TigerCub".

- Remove unwanted ) from end of gold value so that users see "3 Gold" instead of "3) Gold". Bracket had been left over from the end of the old env.t(...) function call - see https://github.com/HabitRPG/habitrpg/commit/4f07ab39b0868764c665bbf914474745e11ecc32

- Add spaces between words so that users see "Sell Fox for 3 Gold" instead of "SellFoxfor3Gold". There are other shorter/neater ways to insert those spaces, but making them really obvious with nbsp is probably the best way to ensure they don't get accidentally removed again.
Merge pull request #2591 from Alys/patch-2

Market "Sell..." button: add spaces, remove bracket