release-26.3.1-rc: testutils/lint: TestNightlyLint failed

testutils/lint.TestNightlyLint [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_LintURLsBazel/21454463?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_LintURLsBazel/21454463?buildTab=artifacts#/) on release-26.3.1-rc @ [5ee8013732b498595a7ca0aa8c20512468f7b8fc](https://github.com/cockroachdb/cockroach/commits/5ee8013732b498595a7ca0aa8c20512468f7b8fc):

```
I260806 06:09:21.342933 100 (gostd) urlcheck.go:245 [-] 11 Checking https://www.cockroachlabs.com/docs/v26.3/show-columns.html...
I260806 06:09:21.342975 56 (gostd) urlcheck.go:245 [-] 12 Checking https://www.cockroachlabs.com/docs/v26.3/set-transaction.html...
I260806 06:09:21.343052 58 (gostd) urlcheck.go:245 [-] 13 Checking https://www.cockroachlabs.com/docs/v26.3/savepoint.html...
I260806 06:09:21.343088 59 (gostd) urlcheck.go:245 [-] 14 Checking https://www.cockroachlabs.com/docs/v26.3/alter-table.html...
I260806 06:09:21.343137 57 (gostd) urlcheck.go:245 [-] 15 Checking https://www.cockroachlabs.com/docs/v26.3/show-partitions.html...
I260806 06:09:21.343185 63 (gostd) urlcheck.go:245 [-] 16 Checking https://www.cockroachlabs.com/docs/v26.3/drop-procedure.html...
I260806 06:09:21.343228 62 (gostd) urlcheck.go:245 [-] 17 Checking https://www.cockroachlabs.com/docs/v26.3/create-table.html...
I260806 06:09:21.343279 98 (gostd) urlcheck.go:245 [-] 18 Checking https://www.cockroachlabs.com/docs/v26.3/drop-table.html...
I260806 06:09:21.343336 102 (gostd) urlcheck.go:245 [-] 19 Checking https://www.cockroachlabs.com/docs/v26.3/backup.html...
I260806 06:09:21.343399 103 (gostd) urlcheck.go:245 [-] 20 Checking https://www.cockroachlabs.com/docs/v26.3/commit-transaction.html...
I260806 06:09:21.587335 285 (gostd) urlcheck.go:245 [-] 21 Checking https://www.cockroachlabs.com/docs/v26.3/create-function.html...
I260806 06:09:21.601003 291 (gostd) urlcheck.go:245 [-] 22 Checking https://www.cockroachlabs.com/docs/v26.3/show-databases.html...
I260806 06:09:21.616282 286 (gostd) urlcheck.go:245 [-] 23 Checking https://www.cockroachlabs.com/docs/v26.3/show-zone-configurations.html...
I260806 06:09:21.632810 306 (gostd) urlcheck.go:245 [-] 24 Checking https://www.cockroachlabs.com/docs/v26.3/cluster-settings.html...
I260806 06:09:21.633758 292 (gostd) urlcheck.go:245 [-] 25 Checking https://www.cockroachlabs.com/docs/v26.3/insert.html...
I260806 06:09:21.641794 287 (gostd) urlcheck.go:245 [-] 26 Checking https://www.cockroachlabs.com/docs/v26.3/alter-partition.html...
I260806 06:09:21.642525 307 (gostd) urlcheck.go:245 [-] 27 Checking https://www.cockroachlabs.com/docs/v26.3/alter-type.html...
I260806 06:09:21.651432 15 (gostd) urlcheck.go:245 [-] 28 Checking https://www.cockroachlabs.com/docs/v26.3/begin-transaction.html...
I260806 06:09:21.674763 16 (gostd) urlcheck.go:245 [-] 29 Checking https://en.wikipedia.org/wiki/Cron...
I260806 06:09:21.690252 297 (gostd) urlcheck.go:245 [-] 30 Checking https://www.cockroachlabs.com/docs/v26.3/revoke.html...
I260806 06:09:21.721750 341 (gostd) urlcheck.go:245 [-] 31 Checking https://www.cockroachlabs.com/docs/v26.3/create-procedure.html...
I260806 06:09:21.723690 342 (gostd) urlcheck.go:245 [-] 32 Checking https://www.cockroachlabs.com/docs/v26.3/drop-index.html...
I260806 06:09:21.724138 359 (gostd) urlcheck.go:245 [-] 33 Checking https://www.cockroachlabs.com/docs/v26.3/show-index.html...
I260806 06:09:21.724435 299 (gostd) urlcheck.go:245 [-] 34 Checking https://www.cockroachlabs.com/docs/v26.3/alter-procedure.html...
I260806 06:09:21.755710 302 (gostd) urlcheck.go:245 [-] 35 Checking https://www.cockroachlabs.com/docs/v26.3/show-default-privileges...
I260806 06:09:21.762418 360 (gostd) urlcheck.go:245 [-] 36 Checking https://www.cockroachlabs.com/docs/v26.3/select-clause.html...
I260806 06:09:21.769676 361 (gostd) urlcheck.go:245 [-] 37 Checking https://www.cockroachlabs.com/docs/v26.3/show-create.html...
I260806 06:09:21.785891 362 (gostd) urlcheck.go:245 [-] 38 Checking https://www.cockroachlabs.com/docs/v26.3/show-tables.html...
I260806 06:09:21.786385 303 (gostd) urlcheck.go:245 [-] 39 Checking https://www.cockroachlabs.com/docs/v26.3/upsert.html...
I260806 06:09:21.786801 367 (gostd) urlcheck.go:245 [-] 40 Checking https://www.cockroachlabs.com/docs/v26.3/truncate.html...
I260806 06:09:21.787262 312 (gostd) urlcheck.go:245 [-] 41 Checking https://www.cockroachlabs.com/docs/v26.3/set-vars.html...
I260806 06:09:21.787887 374 (gostd) urlcheck.go:245 [-] 42 Checking https://www.cockroachlabs.com/docs/v26.3/show-backup.html...
I260806 06:09:21.794459 156 (gostd) urlcheck.go:245 [-] 43 Checking https://www.cockroachlabs.com/docs/v26.3/grant.html...
I260806 06:09:21.803437 346 (gostd) urlcheck.go:245 [-] 44 Checking https://www.cockroachlabs.com/docs/v26.3/table-expressions.html...
I260806 06:09:21.842192 380 (gostd) urlcheck.go:245 [-] 45 Checking https://www.cockroachlabs.com/docs/v26.3/show-users.html...
I260806 06:09:21.867809 314 (gostd) urlcheck.go:245 [-] 46 Checking https://www.cockroachlabs.com/docs/v26.3/drop-function.html...
I260806 06:09:21.868019 381 (gostd) urlcheck.go:245 [-] 47 Checking https://www.cockroachlabs.com/docs/v26.3/delete.html...
I260806 06:09:21.868124 166 (gostd) urlcheck.go:245 [-] 48 Checking https://www.cockroachlabs.com/docs/v26.3/create-table-as.html...
I260806 06:09:21.878657 325 (gostd) urlcheck.go:245 [-] 49 Checking https://www.cockroachlabs.com/docs/v26.3/restore.html...
I260806 06:09:21.895911 434 (gostd) urlcheck.go:245 [-] 50 Checking https://www.cockroachlabs.com/docs/v26.3/rollback-transaction.html...
I260806 06:09:21.900478 440 (gostd) urlcheck.go:245 [-] 51 Checking https://www.cockroachlabs.com/docs/v26.3/alter-index.html...
I260806 06:09:21.910533 445 (gostd) urlcheck.go:245 [-] 52 Checking https://www.cockroachlabs.com/docs/v26.3/show-grants.html...
I260806 06:09:21.914410 446 (gostd) urlcheck.go:245 [-] 53 Checking https://www.cockroachlabs.com/docs/v26.3/show-ranges.html...
I260806 06:09:21.918159 398 (gostd) urlcheck.go:245 [-] 54 Checking https://www.cockroachlabs.com/docs/v26.3/alter-function.html...
I260806 06:09:21.939651 447 (gostd) urlcheck.go:245 [-] 55 Checking https://www.cockroachlabs.com/docs/v26.3/show-constraints.html...
I260806 06:09:21.941095 431 (gostd) urlcheck.go:245 [-] 56 Checking https://www.cockroachlabs.com/docs/v26.3/alter-view.html...
nightly_lint_test.go:44: https://www.cockroachlabs.com/docs/v26.3/alter-trigger.html : 404 Not Found
188: https://www.cockroachlabs.com/docs/v26.3/alter-trigger.html
1 errors
--- FAIL: TestNightlyLint/TestHelpURLs (1.08s)
```
Help

See also: [How To Investigate a Go Test Failure \(internal\)](https://cockroachlabs.atlassian.net/l/c/HgfXfJgM)

Same failure on other branches

- #172711 release-26.3.0-rc: testutils/lint: TestNightlyLint failed [C-test-failure O-robot T-release branch-release-26.3.0-rc release-blocker]

/cc @cockroachlabs/test-eng

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*TestNightlyLint.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Jira issue: CRDB-66481

Start with TestNightlyLint/TestHelpURLs in nightly_lint_test.go and the URL-checking code reported at urlcheck.go:245. Re-run the failing test and inspect the missing alter-trigger.html reference; done means the nightly help-URL check passes without 404 errors.

Written by the indexing model from the issue text.