feat: Add mouse scrolling in file preview

[krivahtoo]

trafficstars

• Add file preview scrolling with the mouse.
• Limit file preview scrolling to the last 3 lines to avoid scrolling way past the last line of the file.

Closes #535

[Zeioth]

Looks good. Video comparison here: https://www.youtube.com/watch?v=CjKcNoJ9VF4

Left: ranger Right: joshuto

[krivahtoo]

Looks good. Video comparison here: https://www.youtube.com/watch?v=CjKcNoJ9VF4

Left: ranger Right: joshuto

Is joshuto scroll speed too fast or ranger is just too slow? 🤔

[Zeioth]

Yes ranger scrolls slower (a bit too much).