The real hose is inside the braided sheath, which is then coated with the clear polymer, and then sheathed again with the black rubber at the ends - mainly to prevent a "kink" in the inner hoses should a sharp bend be experienced at the end.
In short, it looks worse than it is. My real concern is what caused the slash in the first place - whatever it was, I don't want it cutting through to the layer that matters! Check how the lines slinky back and forth under full steering sweep, and adjust the lines to minimize rubbing and avoid any sharp kinking. It can be hard to eliminate all rubbing at full steering lock, but you certainly don't want it rubbing on track at "normal" steering angles.
The slash looks weird, like it is from a tool? Once you eliminate the cause of the slash, I like Frank's idea ... safe to run, but order spares.
Facetiously humorous portion of post: "The 1.6 has a disadvantageous Steering Axis Inclination and Bump Steer Encabulator Joint that causes premature brake line failure, bad tire wear, slow lap times, and increased risk of herpes!"