Linux kernel upgrade doc: point to raw debian/changelog

It's easier to copy'n'paste the relevant bits from this view
into one's text editor.

wiki/src/contribute/Linux_kernel.mdwn

@@ -102,7 +102,7 @@ To learn how the new kernel works for us:
 
 You'll find the relevant data in:
 
- - [Changelog](https://salsa.debian.org/kernel-team/linux/blob/sid/debian/changelog?expanded=true&viewer=simple)
+ - [Changelog](https://salsa.debian.org/kernel-team/linux/raw/sid/debian/changelog)
    of the Debian package
  - Kernelnewbies's [human-readable
    changelog](https://kernelnewbies.org/LinuxChanges) of upstream