fix: reload window button not working

[gaspardruan]

When clicking the reload window button, nothing happened. The console reported the error

I just changed one line and it works fine.

- onClick={window.ElectronFiddle.reloadWindows}
+ onClick={() => window.ElectronFiddle.reloadWindows()}

[coveralls]

coverage: 87.245% (-0.02%) from 87.262%
when pulling e1125bd on gaspardruan:fix-reload-button
into d577648 on electron:main.

[dsanders11]

Thanks!