Fix wrong task name on watch for next/export files (#7204)

packages/next/taskfile.js

@@ -153,7 +153,7 @@ export default async function (task) {
   await task.watch('pages/**/*.+(js|ts|tsx)', 'pages')
   await task.watch('server/**/*.+(js|ts|tsx)', 'server')
   await task.watch('build/**/*.+(js|ts|tsx)', 'nextbuild')
-  await task.watch('export/**/*.+(js|ts|tsx)', 'nextexport')
+  await task.watch('export/**/*.+(js|ts|tsx)', 'nextbuildstatic')
   await task.watch('client/**/*.+(js|ts|tsx)', 'client')
   await task.watch('lib/**/*.+(js|ts|tsx)', 'lib')
   await task.watch('cli/**/*.+(js|ts|tsx)', 'cli')