Update BaseLib according to code review comments.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@5956 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/BaseLib/LinkedList.c

@@ -25,7 +25,7 @@
 
   If List is NULL, then ASSERT().
   If List->ForwardLink is NULL, then ASSERT().
-  If List->backLink is NULL, then ASSERT().
+  If List->BackLink is NULL, then ASSERT().
   If Node is NULL, then ASSERT();
   If PcdMaximumLinkedListLenth is not zero, and prior to insertion the number
   of nodes in ListHead, including the ListHead node, is greater than or
@@ -384,7 +384,7 @@ IsNodeAtEnd (
   @param  FirstEntry  A pointer to a node in a linked list.
   @param  SecondEntry A pointer to another node in the same linked list.
   
-  @return SecondEntry
+  @return SecondEntry after the nodes are swapped
 
 **/
 LIST_ENTRY *
@@ -411,7 +411,7 @@ SwapListEntries (
   Ptr = RemoveEntryList (FirstEntry);
 
   //
-  // If FirstEntry immediately follows SecondEntry, FirstEntry willl be placed
+  // If FirstEntry immediately follows SecondEntry, FirstEntry will be placed
   // immediately in front of SecondEntry
   //
   if (Ptr->BackLink == SecondEntry) {
@@ -452,7 +452,9 @@ SwapListEntries (
 
   @param  Entry A pointer to a node in a linked list
 
-  @return Entry
+  @return The node following Entry in the doubly linked list.
+          If Entry is the only node in the linked list, then
+          the head node of the linked list is returned.
 
 **/
 LIST_ENTRY *