This is the convention for how to indicate a line break in a poem/song when writing two lines together, and you can see it reflected in the Episode Titles on the website. These titles are all lines from the in-universe "Ballad of the Witches Road".

You're right that on screen there's no slash, but they ARE on separate lines (which is what the slash represents).

@jedi.jesse said:

You're right that on screen there's no slash, but they ARE on separate lines (which is what the slash represents).

This is not true for at least two of the episodes https://postimg.cc/gallery/QWNxq9X