feat: autoplay next word when pressing enter on keyboard in practice mode

[kaelonR]

In practice mode, We can use the enter key to submit a word, but then still have to click the play button with the mouse to hear the next word.

This PR fixes this. When submitting via the enter key, the next word will play automatically after 250 milliseconds. The 250ms delay is there to make sure there isn't an abrupt change from one soundtrack into another which can make the word difficult to hear.

[gruelingpine185]

dang... you beat me to it.

[wmpedersen]

Just referencing my commit here - I do like the idea of autoplaying for the one-word interfaces like youtube or spelloff as well if you could add it, though I know they're kind of hidden modes.