The rel arm required a leading `./` or `../`, so `[x](swarm/services.md)` —
the form a sibling link is usually written in — matched none of the three
arms. That is exactly the shape a directory move breaks: during #3911 a link
in that form moved into a new directory, resolved to nothing, and the lint
stayed green. Reproduced by putting the broken form back with `sed`
(MUTATED_DIRTY=1) and re-running: exit 0, a control that fails to fail.
Widening the pattern surfaces 116 links the arm never saw (76 -> 192 matches).
111 are in `.md` files and all 111 resolve today, so this adds coverage
without a single new failure in the tree; the other 5 are the interesting
part, and they are why the arm now selects on file type.
A link is only resolvable against its own directory when the file is
*rendered where it is stored*. The four in `nix/docs/default.nix` are inside
a markdown string this derivation writes to `$out`, and the one in
`hive-c0re/src/workers/knowledge.rs` is template text for another repo's
README — resolving either from the source directory certifies a path no
reader ever requests. `lint:allow` is the wrong tool for them: the marker
lives inside the generated text, so it would ship in the published page.
The `.rs` arm keeps its error, narrowed to doc-comment lines. Its premise
still holds — the repo has zero relative links in `.rs` doc comments — but
without the narrowing the widened pattern reports the knowledge.rs template
string with a message about rustdoc that is wrong for it.
Measured: the old arm's 76 hits are all in `.md` files, so restricting
resolution to `.md` removes no existing coverage.
Closes#4076
484b8b1129