fix: import jsx when needed

src/components/ScreenManager/ScreenManager.tsx

@@ -1,4 +1,4 @@
-import { useContext } from 'react'
+import { JSX, useContext } from 'react'
 import { TrainerContext } from '../TrainerProvider'
 
 interface ScreenManagerProps {

src/components/SoundfontProvider/SoundfontProvider.tsx

@@ -1,6 +1,6 @@
 // Based on SoundfontProvider
 // https://github.com/kevinsqi/react-piano/blob/master/demo/src/SoundfontProvider.js
-import { useCallback, useEffect, useMemo, useState } from 'react'
+import { JSX, useCallback, useEffect, useMemo, useState } from 'react'
 import Soundfont, { InstrumentName, Player } from 'soundfont-player'
 
 interface SoundfontProviderProps {