Brief Summary
When we enter something in a search bar the only way to move between suggestions is trackpad/mouse or arrow keys which is not really convenient.
Details:
My suggestion is to add the ability to move to the next suggestion with a Tab key which is already pretty common in browsers: for example we can use tab to move to other buttons or other elements of the interface in the website.
In the video below I show an example how it might work as a feature: firstly I show that tab doesn't do a thing (you can watch pressed keys in a right bottom corner) and then I show that we can move between suggestions only with arrows.
Image/Video: