fix: match bracketed guest credits and hyphenated version suffixes

Two normalisation faults, both found by running a real coverage report's
unmatched list back through the normaliser. Between them they account for five
of the fifteen worst misses by play count.

The guest-credit pattern required whitespace immediately before the word, so it
caught "Yellowcard feat. Tay Jardine" but missed "Self vs Self (feat. In
Flames)" -- and the bracketed form is the more common of the two. An opening
bracket is now allowed in that position.

The trailing-version pattern matched the suffix as a run of non-hyphens, which
cannot cross a hyphen inside the suffix itself: "Gold Dust - Shy FX Re-Edit" and
"Back To Your Roots - Friction & K-Tee Remix" both survived untouched. Matched
lazily instead.

Four version words are added for how drum and bass marks its variants: vip,
bootleg, rework, extended. They only apply inside a bracket or after a trailing
dash, so the exposure is small, and ordinary titles carrying those words --
Editors, Mixed Emotions, Radio Ga Ga, Live and Let Die -- are pinned as tests
against exactly that.

The report also gains the figures that explain why the MBID tier contributes so
little. Two thirds of scrobbles carry a recording id, and only a twentieth of
them join on one: MusicBrainz holds a separate recording per release, and the
two sides rarely choose the same one. Counting the pairs that carried an id and
matched on name anyway measures that disagreement directly, and settles that the
weakness is not a bug in the join.

README.md

@@ -29,7 +29,14 @@ Two tiers, and no third.
 | `name` | Normalised artist and title | Everything the first tier could not carry |
 | `none` | — | Recorded as a miss, never guessed at |
 
-The normalisation is the load-bearing part, because the two sides disagree in
+The name tier does almost all of the work. A recording MBID is exact when it
+lands, but MusicBrainz holds a separate recording per release, and Last.fm and
+Lidarr rarely pick the same one: on a real library, two thirds of scrobbles
+carry a recording id and barely a twentieth of them join on it. The report
+counts how many carried an id and matched on name anyway, which is the measure
+of that disagreement.
+
+So the normalisation is the load-bearing part, because the two sides disagree in
 predictable ways. It folds case and accents, drops guest credits (`Yellowcard
 feat. Tay Jardine` against a tag of `Yellowcard`), strips a trailing
 version suffix (`(Remastered 2011)`, `- Live`), expands `&`, and removes a