Documenting that resolved JIRA tickets are not automatically transitioned

What does this MR do?

Adding to JIRA integration documentation that resolved JIRA issues are not automatically transitioned

Are there points in the code the reviewer needs to double check?

Why was this MR needed?

Users might think that the integration is not correctly parametrized whereas it is correctly working. cf discussion https://gitlab.com/gitlab-org/gitlab-ce/issues/33522#note_52795564 .

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• [N/A] API support added
• [N/A] Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered

What are the relevant issue numbers?

https://gitlab.com/gitlab-org/gitlab-ce/issues/33522#note_52795564