Update verbiage to say Save instead of Close in Project Preferences

It would ease my mind and possibly others if the close button instead said “Save.“ If I spent a decent amount of time updating this section, I would like to be certain that closing the popup is in fact also saving it. And vice versa, maybe I don’t want to save the changes, and I just want to close the popup without saving, you would hit the close button, or just clicking the ‘X’