Use Mouse4 and Mouse5 for back/forward in sideview.

[dakshcs]

I have a mouse with thumb triggers along with the regular 3 buttons.

Due to this, I have developed a habit of going back/forward with mouse4 and mouse5 as it is standard to bind these buttons to back and forward (ex- in windows, file explorer, even on linux with kde/gnome and basically every DE ever.)

It annoys me a lot that this behaviour is already in firefox but when I try to use it in sideview, it applies to the main tab instead of the sideview tab, despite clicking on the sideview tab to get it in focus/foreground.

mozilla pls fix.

(Zen already does this btw... maybe lift the code from there?)

[dakshcs]

just found out that the extension isn't actively being developed.

rip.