Source Editor: Add a scroll/don't extend past end of page

[SharonStrats]

I opened this since the original ticket is complete for the source editor card. Also, I wanted to discuss when we should add this.

Here are my thoughts:
Currently the new source editor card sits in the old folder-pane. This means when you select a document in the middle of the screen or further down it opens at the bottom, it's very small so I think it would look funny right now to add the scroll or to make it only show the portion that fits in the screen. Here is how it looks.

Also, I thought I'd do a bit of research and I noticed that for github there is no scroll on the file itself only on the main window. After seeing this I wonder if we want to add the scroll and make it fit in the window after all.
https://github.com/SolidOS/profile-pane/blob/main/src/ProfileView.ts

Wanted to get your thoughts.

[timea-solid]

I think we need a intermediate solution that looks ok for now since the editor is still inside the file explorer tree. I trust your decision on how to make it look good for now. Later we will probably change the scroll again.