feat: create new page for the unused return value checker#5169

daniCsorbaJB wants to merge 6 commits into2-3-0-doc-updateJetBrains/kotlin-web-site:2-3-0-doc-updatefrom

unused-return-value-checker-docJetBrains/kotlin-web-site:unused-return-value-checker-docCopy head branch name to clipboard