fix: manually type ThemeProvider to fix type errors (pacocoursey#263)

* fix: manually type ThemeProvider to fix type errors

* Update next-themes/src/index.tsx

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Co-authored-by: paco <34928425+pacocoursey@users.noreply.github.com>

next-themes/src/index.tsx

@@ -12,7 +12,7 @@ const defaultContext: UseThemeProps = { setTheme: _ => {}, themes: [] }
 
 export const useTheme = () => React.useContext(ThemeContext) ?? defaultContext
 
-export const ThemeProvider = (props: ThemeProviderProps) => {
+export const ThemeProvider = (props: ThemeProviderProps): React.ReactNode => {
   const context = React.useContext(ThemeContext)
 
   // Ignore nested context providers, just passthrough children