SwiftDocCTextIndexingProtocolTextIndexingA value that can collect plain text content for use in search indexing.protocol TextIndexingTopicsInstance Propertiesvar headings: [String]Headings and sub-headings to drive search results.Instance Methodsfunc rawIndexableTextContent(references: [String : any RenderReference]) -> StringA concatenation of all raw text content under this value except for titles and headings.