minor javadoc review

[Mike Duigou]

Hello all;

For your consideration a minor javadoc fix to review for TreeMap. This change makes the TreeMap documentation consistent with the SortedMap documentation. The primary fix is to add the word "sorted" in the sentence :

> This is so because the <tt>Map</tt> interface is defined in terms of the {@code equals} operation, but a +++sorted+++ map performs all key comparisons using its {@code compareTo} (or {@code compare}) method, so two keys that are deemed equal by this method are, from the standpoint of the sorted map, equal. 

The other changes are to replace <i> -> <em> and <tt>...</tt> -> {@code ...}

6465367: (coll) Typo in TreeMap documentation
webrev @ http://cr.openjdk.java.net/~mduigou/6465367.0/webrev

Thanks!

Mike