doc: fix release-schedule link in backport guide

PR-URL: #35920
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/guides/backporting-to-release-lines.md

@@ -90,5 +90,5 @@ After the pull request lands, replace the `backport-requested-v10.x` label
 on the original pull request with `backported-to-v10.x`.
 
 [Release Plan]: https://github.com/nodejs/Release#release-plan
-[Release Schedule]: https://github.com/nodejs/Release#release-schedule1
+[Release Schedule]: https://github.com/nodejs/Release#release-schedule
 [`node-test-pull-request`]: https://ci.nodejs.org/job/node-test-pull-request/build