SwiftDocCDuplicateTopicsSectionsStructureDuplicateTopicsSectionsA Document may only have one level-2 “Topics” heading at the top level, since it serves as structured data for a documentation bundle’s hierarchy.struct DuplicateTopicsSectionsTopicsInitializersinit(sourceFile: URL?)Creates a new checker that detects documents with multiple “Topics” sections.Instance Propertiesvar foundTopicsHeadings: [Heading]The list of level-2 headings with the text “Topics” found in the document.var problems: [Problem]Instance Methodsfunc visitHeading(Heading)