The two prefix-parsing tests were pinned to `artist:Eric`, but `artist`
was removed from KNOWN_KINDS in commit 4cad07a (provenance is a separate
axis from tags). The parser now keeps `artist:` literal, so the assertion
`body["name"] == "Eric"` failed.
Repointed to `character:Saber` (still in KNOWN_KINDS). Also updated the
stale `artist:` docstring example in parse_kind_prefix to `fandom:`.
Caught by [[reference-grep-pinned-tests-in-plans]] — should have grep'd
tests/ for `artist:` when shrinking KNOWN_KINDS. Banking the miss.
bvandeusen
8675f105ad