Update markdown.swift

Author: Alexander-Ignition

Scripts/markdown.swift

@@ -3,7 +3,7 @@
 /*
  OVERVIEW: Convert Xcode Playground to markdown
 
- USAGE: cat Playgrounds/Example.playground/Contents.swift | ./Scripts/markdown.swift
+ USAGE: cat Playgrounds/README.playground/Contents.swift | ./Scripts/markdown.swift
  */
 
 enum TextBlock {
@@ -13,20 +13,23 @@ enum TextBlock {
 var block = TextBlock.unknown
 
 while let line = readLine() {
-    if line.hasPrefix("/*") {
-        if block == .code {
-            print("```")
-        }
+    switch block {
+    case .unknown where line.isEmpty:
+        break
+    case .unknown where line.hasPrefix("/*"):
         block = .comment
-    } else if line.hasSuffix("*/") {
-        print("```swift")
+    case .unknown:
         block = .code
-    } else if block == .comment {
-        print(line.drop(while: \.isWhitespace))
-    } else {
+        print("```swift")
         print(line)
+    case .code where line.hasPrefix("/*"):
+        block = .comment
+        print("```")
+    case .code:
+        print(line)
+    case .comment where line.hasSuffix("*/"):
+        block = .unknown
+    case .comment:
+        print(line.drop(while: \.isWhitespace))
     }
 }
-if block == .code {
-    print("```")
-}