The OpenAPI coverage test fails on a NOT_YET_DESCRIBED entry that is now described, and the stale entries leave #5396

For: the list in test/openapi-coverage.test.ts says what is still undescribed, truthfully. Pulls that add rows have left their entries behind, because a described entry is ignored and only logged (removable, near line 183). The list on main still names routes that #5240, #5241, #5242, #5245, #5040, #5150 and #5153 described.

Done:

• [ ] The second test also expects NOT_YET_DESCRIBED.filter((r) => described.has(r)) to be [], with a message naming each stale line to delete. The console.log goes.
• [ ] Every stale entry is deleted in the same pull, so the test is green on main.
• [ ] The comment above the list says that describing a route means deleting its line, and that the test fails until you do.

Files: test/openapi-coverage.test.ts only. Risk: the open OpenAPI issues (#5113–#5116, #5310–#5315, #5380–#5383 and others) delete lines too. Delete only lines that are described on main when you start, and rebase before pushing.