Update displayed code to use 2 space indentation

Author: jawwad

Heap Sort/README.markdown

@@ -48,13 +48,13 @@ Here's how you can implement heap sort in Swift:
 
 ```swift
 extension Heap {
-    public mutating func sort() -> [T] {
-        for i in stride(from: (elements.count - 1), through: 1, by: -1) {
-            swap(&elements[0], &elements[i])
-            shiftDown(0, heapSize: i)
-        }
-    return elements
+  public mutating func sort() -> [T] {
+    for i in stride(from: (elements.count - 1), through: 1, by: -1) {
+      swap(&elements[0], &elements[i])
+      shiftDown(0, heapSize: i)
     }
+    return elements
+  }
 }
 ```
 
@@ -71,9 +71,9 @@ We can write a handy helper function for that:
 
 ```swift
 public func heapsort<T>(_ a: [T], _ sort: @escaping (T, T) -> Bool) -> [T] {
-    let reverseOrder = { i1, i2 in sort(i2, i1) }
-    var h = Heap(array: a, sort: reverseOrder)
-    return h.sort()
+  let reverseOrder = { i1, i2 in sort(i2, i1) }
+  var h = Heap(array: a, sort: reverseOrder)
+  return h.sort()
 }
 ```