AttribuedString markdown parsing

markdown.swift

let attrString = try AttributedString(markdown: markdown)

for (intentBlock, intentRange) in attrString.runs[\.presentationIntent] {
    guard let intentBlock else { continue }
    for intent in intentBlock.components {
        switch intent.kind {
        case .paragraph:
        case let .header(level):
        case .orderedList:
        case .unorderedList:
        case let .listItem(ordinal):
        case let .codeBlock(languageHint):
        case .blockQuote:
        case .thematicBreak:
        case let .table(columns):
        case .tableHeaderRow:
        case let .tableRow(rowIndex):
        case let .tableCell(columnIndex):
        }
    }
}