Conform to code standards by adding (some) documentation

Author: mindgraffiti

WordPressShared/Core/Utility/CollectionType+Helpers.swift

@@ -1,5 +1,8 @@
 import Foundation
 
+
+// MARK: - Collection Type Helpers
+//
 extension BidirectionalCollection {
     public func lastIndex(where predicate: (Self.Iterator.Element) throws -> Bool) rethrows -> Self.Index? {
         if let idx = try reversed().firstIndex(where: predicate) {
@@ -10,8 +13,8 @@ extension BidirectionalCollection {
 }
 
 extension Collection {
-
     /// Returns the element at the specified index if it is within bounds, otherwise nil.
+    ///
     public subscript (safe index: Index) -> Element? {
         return indices.contains(index) ? self[index] : nil
     }