Gemini parser cleanup

GeminiFormat/GeminiParser.swift

@@ -14,28 +14,24 @@ public struct GeminiParser {
     public static func parse(text: String, baseURL: URL) -> Document {
         var doc = Document(url: baseURL)
         
-        var preformattingState = PreformattingState.off
+        var inPreformattingBlock = false
         text.enumerateLines { (line, stop) in
             if line.starts(with: "```") {
-                switch preformattingState {
-                case .off:
+                if inPreformattingBlock {
+                    inPreformattingBlock = false
+                    // todo: should the toggle off line be a separate line type?
+                    doc.lines.append(.preformattedToggle(alt: nil))
+                } else {
                     let alt: String?
                     if line.count > 3 {
                         alt = String(line[line.index(line.startIndex, offsetBy: 3)...])
                     } else {
                         alt = nil
                     }
-                    preformattingState = .on(alt)
+                    inPreformattingBlock = true
                     doc.lines.append(.preformattedToggle(alt: alt))
-                case let .on(alt):
-                    preformattingState = .off
-                    // todo: should the toggle off line be a separate line type?
-                    doc.lines.append(.preformattedToggle(alt: nil))
                 }
-                if case .off = preformattingState {
-                    
-                }
-            } else if case .on(_) = preformattingState {
+            } else if inPreformattingBlock {
                 doc.lines.append(.preformattedText(line))
             } else if line.starts(with: "=>") {
                 // Link line