Mark Enabled API for synchronous instruments stable

[codeboten]

Fixes #4215

Changes

This marks the API stable. The prototypes are discussed in the issue.

• [x] Related issues #4215
• [x] Links to the prototypes (when adding or changing features)
• [x] CHANGELOG.md file updated for non-trivial changes
• [x] spec-compliance-matrix.md updated if necessary

[carlosalberto]

cc @jmacd

[github-actions[bot]]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[github-actions[bot]]

Closed as inactive. Feel free to reopen if this PR is still being worked on.