chore: improve changelog

[barmac]

Proposed Changes

This moves new feel-lint feature to the General section as it's available in all editors.

Checklist

To ensure you provided everything we need to look at your PR:

• Brief textual description of the changes present
• Visual demo attached
• Steps to try out present, i.e. using the @bpmn-io/sr tool
• Related issue linked via Closes {LINK_TO_ISSUE} or Related to {LINK_TO_ISSUE}

[nikku]

Also added the 8.6 built-ins to the general section.

[nikku]

Thanks!