Clarify what a user-facing change is for changelogs

What does this MR do?

Clarifies what a user-facing change is for changelog entries.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

N/A

Security

N/A