Fix rare markdown crash

damus/Util/Markdown.swift

@@ -8,8 +8,8 @@
 import Foundation
 
 public struct Markdown {
-    private let detector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
-
+    private var detector = try? NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
+    
     /// Ensure the specified URL has a scheme by prepending "https://" if it's absent.
     static func withScheme(_ url: any StringProtocol) -> any StringProtocol {
         return url.contains("://") ? url : "https://" + url
@@ -31,6 +31,9 @@ public struct Markdown {
 
     /// Process the input text and add markdown for any embedded URLs.
     public func process(_ input: String) -> AttributedString {
+        guard let detector else {
+            return AttributedString(stringLiteral: input)
+        }
         let matches = detector.matches(in: input, options: [], range: NSRange(location: 0, length: input.utf16.count))
         var output = input
         // Start with the last match, because replacing the first would invalidate all subsequent indices