{github.raw} links do not work in surge previews

[holly-cummins]

Either that, or I just merged a change with a dead link :) (We probably should have link-checking integration tests, if we don't already, but getting them checking against the right relative path can be non trivial.)

For example, I couldn't validate the following link in a PR, but it worked locally: https://raw.githubusercontent.com/quarkusio/quarkus-workshops/refs/pull/304/merge/quarkus-workshop-super-heroes/super-heroes/rest-fights/src/test/java/io/quarkus/workshop/superheroes/fight/FightResourceConsumerTest.java

Edit: Link was fine live, broken in preview.

[agoncal]

Having link-checking integration tests would be great