Fix rake db:migrate:status typo in docs

What does this MR do?

Corrects typo, changes non-working gitlab-rake db:migrations:status command to working db:migrate:status

In my attempt to close https://gitlab.com/gitlab-org/gitlab-ce/issues/63908 with https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/30202 , I introduced a typographical error affecting the command instruction itself. 😦 Sorry for not catching this sooner.

The correct db:migrate:status command is referred to everywhere other than the code block.

This fixes the typographical error to prevent confusion and unexpected errors on the command line.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content