Add cycle analytics duration chart to docs
What does this MR do?
This MR updates the cycle analytics documentation by mentioning the introduction of the
days to completion chart.
- Follow the Documentation Guidelines and Style Guide.
- [-] If applicable, update the permissions table.
- [-] Link docs to and from the higher-level index page, plus other related docs where helpful.
- Apply the documentation label.
1. Primary Reviewer
- Review by a code reviewer or other selected colleague to confirm accuracy, clarity, and completeness. This can be skipped for minor fixes without substantive content changes.
2. Technical Writer
- Optional: Technical writer review. If not requested for this MR, must be scheduled post-merge. To request for this MR, assign the writer listed for the applicable DevOps stage.
- Review by assigned maintainer, who can always request/require the above reviews. Maintainer's review can occur before or after a technical writer review.
- Ensure a release milestone is set.
- If there has not been a technical writer review, create an issue for one using the Doc Review template.