Fix minor typos

Author: tracicot

include/swift/Runtime/Concurrent.h

@@ -44,7 +44,7 @@ template <class ElemTy> struct ConcurrentList {
   }
 
   /// Remove all of the links in the chain. This method leaves
-  /// the list at a usable state and new links can be added.
+  /// the list at an usable state and new links can be added.
   /// Notice that this operation is non-concurrent because
   /// we have no way of ensuring that no one is currently
   /// traversing the list.
@@ -145,7 +145,7 @@ template <class KeyTy, class ValueTy> struct ConcurrentMapNode {
 /// The method findOrAllocateNode searches the binary tree in search of the
 /// exact Key value. If it finds an edge that points to NULL that should
 /// contain the value then it tries to compare and swap the new node into
-/// place. If it looses the race to a different thread it de-allocates
+/// place. If it loses the race to a different thread it de-allocates
 /// the node and starts the search again since the new node should
 /// be placed (or found) on the new link. See findOrAllocateNode for more
 /// details.
@@ -164,7 +164,7 @@ template <class KeyTy, class ValueTy> class ConcurrentMap {
   /// accelerating the search of the same value again and again.
   std::atomic<NodeTy *> LastSearch;
 
-  /// Search a for a node with key value \p. If the node does not exist then
+  /// Search for a node with key value \p. If the node does not exist then
   /// allocate a new bucket and add it to the tree.
   ConcurrentList<ValueTy> &findOrAllocateNode(KeyTy Key) {
     // Try looking at the last node we searched.