Clean up release template file
The recently added release-template.md is a template for release notes. Some of the items seems redundant and I'm not really sure what the difference is anymore. These seem redundant:
- ANSI compliance fixes
- Bug fixes
- Gitlab tickets
Perhaps we should only have "Gitlab tickets". Maybe keep "ANSI compliance fixes" if we really want to highlight that, but then it's not clear if we duplicate issue numbers here and in "Gitlab tickets".
I don't remember what "Known issues" is for; we have a bug tracker now. I guess "Feature enhancements" are for new, larger changes that we want to emphasize that isn't adequately explained in the issue list.