Someone else not English speaker also thought “Ripple” means a blank region of time also known as a gap. It is because there is an Action in Shotcut named “Ripple Delete” so it sounds like Ripple is the name of an object. However, the meaning of Ripple is explained in the Glossary of the User Guide. It it easy, right-click and choose Ripple Delete. Alternatively, you can turn on Ripple edit mode:
And drag the clip to the right of the gap leftward to close the gap.