Broken links if value contains backslash

[cyco]

Hi,

I noticed that db.libretro.com sometimes interprets backslashes as directory separators and generates invalid links. You can take a look at https://db.libretro.com/Sony%20-%20PlayStation/Alundra%20(USA).html where the linked developer page is invalid. The linked page is https://db.libretro.com/developer/Matrix%20Software%20/Contrail.html but should be https://db.libretro.com/developer/Matrix%20Software%20%5CContrail.html.

I think \ should be added to scrubIllegalChars in https://github.com/libretro/webdb/blob/master/main.go#LL26C3-L26C3

Edit: https://stackoverflow.com/a/10444621 suggests \ in urls are invalid and browsers are trying to do some error recovery.