Clarify changelog type field for feature flag removal

What does this MR do?

It is unclear which type field to use when removing a feature flag. I specified a few different cases by using a state diagram.

The reason being I have seen many MRs with different types for feature flag removal (changes/removed/other), and I feel some might be confusing to the reader.

Does this MR meet the acceptance criteria?

Conformity

• 📋 Does this MR need a changelog?
  • I have included a changelog entry.
  • I have not included a changelog entry because this is not user facing.
• Documentation (if required)
• Code review guidelines
• Style guides