ship finish: FIX_CHECK names the grant that covers the fix-check (GST-1610) (#4070)

* test: failing-first FIX_CHECK names the covering grant with two grants at different heads (GST-1610)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

* fix(ship): finish names the grant whose stop head is newest in the fix-check range (GST-1610)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

* docs: FIX_CHECK grant attribution (GST-1610)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

* docs: changelog fragment prose lint (GST-1610)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

---------

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

docs/review-policy.md

@@ -694,7 +694,9 @@ holding the reviewed tree, and for which an approved `review_loop_grant` in
 that is unchanged since, or whose change against the base is still the one the
 fix-check read after a base merge also edited it (GST-1195), routes as
 `fix_checked=` in `ROUTE:` and is listed on a
-`FIX_CHECK: reviewed` line, a gate-edited test included. Authored docs keep the
+`FIX_CHECK: reviewed` line, a gate-edited test included. The line names the
+grant whose stop head is newest in that range, the fix-check's own when several
+grants fall inside it (GST-1610). Authored docs keep the
 stage 2.2 recheck, and a path the branch edited after the fix-check still routes by the
 rules above. Any other row prints
 `FIX_CHECK: not counted (<reason>)` and changes nothing. `gstack-review-log`