release.sh: notes via git log -n (head broke the pipe under pipefail past 20 commits)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tool/release.sh

@@ -53,7 +53,7 @@ SERVER="$(echo "$ORIGIN" | sed -E 's#(https?://[^/]+)/.*#\1#')"
 REPO="$(echo "${ORIGIN%.git}" | sed -E 's#.*[:/]([^/]+/[^/]+)$#\1#')"
 PROTO="$(sed -n 's/.*protoVersion = \([0-9]*\).*/\1/p' "$ROOT/packages/core/lib/src/constants.dart")"
 if [[ -n "$LATEST" && "$LATEST" != "v$VER" ]]; then
-  NOTES="$(git -C "$ROOT" log "$LATEST..HEAD" --format='- %s' | head -n 20)"
+  NOTES="$(git -C "$ROOT" log -n 20 "$LATEST..HEAD" --format='- %s')"
 else
   NOTES="Watch together $VER."
 fi