typo in event on_gui_opened field description

[benlove007]

https://lua-api.factorio.com/stable/eve ... gui_opened says that the player_index is the "The player closing the GUI." It should say the player opening the GUI. Looks like it was a copy-paste error from the on_gui_closed event.

[Therenas]

Thanks for spotting that, fixed for the next release.