Better handling of changelog files

[justbispo]

Have you checked the readme and man page for this feature?
Yes
Have you checked previous issues for this feature?
Yes

Currently, changelog files are treated like any other file that are included in an AUR repo, they get included in the diff comparison and are installed in the right place.
But I think they should have a different treatment. Doing a diff comparison in a changelog often leads to a cluttered and less readable presentation of the changes.
A few options could help this:

• Show changes separated from the diff comparison
  The changes could be shown before the diff comparison, so the user could decide whether to update a package or not based on the new changes and features.
• Only show changes from the last version or the version being installed
  This aligns better with the purpose of a changelog, which is to inform users about what has changed since the last version they used.
• Use a different text renderer
  Since a diff comparison isn't needed, an option to use a different renderer, like glow, could be added. This option could also be used for the -Qc option (tho this seems more like a feature for pacman).

I think these options could help us knowing what happens in the software we use instead of blindly accepting updates before knowing what changed. It could also make AUR maintainers include changelogs more often, PKGBUILD files even include a field especifically for this but rarely used.