What's a straight vertical line in japanese at the end?

It says on the internet, it's a punctuation used to extend the sound.
Plz rate me if you want to.

In paragraph 47, it says “moments like these make a pioneering flight anything but dull” i’d say he’s optimistic and determined? ? and in 48, it describes how i’m assuming people he looks up to walked the same path so maybe he’s honored to be on the journey ? sorry if i’m wrong.