Use redirect.github.com links when creating Fixes, Refs, PR-URL and Backport-PR-URL

Sometimes I get bothered by the cross references automatically created by GitHub cluttering the referenced PR/issue, especially when they get copied into various forks and each fork would generate a new cross reference. Then the thread of the referenced PRs/issues would eventually get drowned by these cross references over time.

I learned from Bluesky that the documented way to prevent this from happening is to use redirect.github.com instead. So it seems helpful to use that in the metadata generated for commit messages. We can still create direct cross references when we reference them in a comment/PR description, which don't usually get copied all over the place in a way out of our control.

cc @nodejs/tsc @nodejs/release @nodejs/build for visibility since it'll impact the formatting of commit messages, not sure if that'll break anything..

No file or test is named. Start by searching the repository for the metadata fields Fixes, Refs, PR-URL, and Backport-PR-URL, then read the entry point that formats commit messages. Done means those generated links use redirect.github.com while manually written comment and pull-request references remain unchanged.