Port trigger-error.js to TypeScript (#51185)

Author: Peter Bengtsson

src/frame/middleware/index.ts

@@ -35,7 +35,7 @@ import archivedEnterpriseVersions from '@/archives/middleware/archived-enterpris
 import robots from './robots'
 import earlyAccessLinks from '@/early-access/middleware/early-access-links'
 import categoriesForSupport from './categories-for-support'
-import triggerError from '@/observability/middleware/trigger-error.js'
+import triggerError from '@/observability/middleware/trigger-error'
 import secretScanning from '@/secret-scanning/middleware/secret-scanning.js'
 import ghesReleaseNotes from '@/release-notes/middleware/ghes-release-notes.js'
 import whatsNewChangelog from './context/whats-new-changelog.js'

src/observability/middleware/trigger-error.js renamed to src/observability/middleware/trigger-error.ts

@@ -1,7 +1,15 @@
+import type { Response, NextFunction } from 'express'
+
+import type { ExtendedRequest } from '@/types'
+
 // This module is for testing our handling of uncaught async rejections on incoming requests
 
 // IMPORTANT: Leave this function as `async` even though it doesn't need to be!
-export default async function triggerError(req, res, next) {
+export default async function triggerError(
+  req: ExtendedRequest,
+  res: Response,
+  next: NextFunction,
+) {
   // IMPORTANT:
   // Do NOT wrap this method's contents in the usual `try-catch+next(error)`
   // pattern used on async middleware! This is an intentional omission!