Fix typo in comment

Author: florianreinhart

stdlib/public/core/HashedCollections.swift.gyb

@@ -53,7 +53,7 @@ import SwiftShims
 // does not use tombstones.
 //
 // In addition to the native storage `Dictionary` can also wrap an
-// `NSDictionary` in order to allow brdidging `NSDictionary` to `Dictionary` in
+// `NSDictionary` in order to allow bridging `NSDictionary` to `Dictionary` in
 // `O(1)`.
 //
 // Currently native storage uses a data structure like this::