The repositories moved off LINUXexpert-org. Here that is not a
documentation change: the old organisation was the module path, so it is
declared in go.mod and repeated in every internal import.
Leaving it would have been worse than a stale link. GitHub redirects the
repository, but a go.mod whose module line disagrees with the path it was
fetched from is an error rather than a redirect, so `go get` on the new
address would have failed against the old declaration.
go.mod, 34 files of imports, and the repository links in README and
ARCHITECTURE. go mod tidy leaves go.sum untouched -- no dependency moved,
only our own path.