enable option to start new test when one test is completed

[radlinskii]

Currently on the completed test screen we only have a <Esc> mapping for quitting the app, we could add an s mapping to start new test

[log1-codes]

Hey @radlinskii can i work on that issue...kindly assign it to me please

[Sarthak0419]

@radlinskii I would like to contribute to this