Add section Manually update the translation levels

What does this MR do?

Per this suggestion, this MR updates the documentation related to #328430 (closed)

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because _____.
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content