Update the code commit link in Help page to jihulab.com

Problem to solve

We have migrated JH GitLab repo from https://gitlab.com/gitlab-jh/gitlab to https://jihulab.com/gitlab-cn/gitlab, but the code commit link in the Help page (e.g. https://jihulab.com/help) still points to https://gitlab.com/gitlab-jh/gitlab.

Proposal

Change the code commit link to https://jihulab.com/gitlab-cn/gitlab.