BUG#16393: post-review fixes: fix comments.

sql/sql_select.cc

@@ -2931,28 +2931,20 @@ sort_keyuse(KEYUSE *a,KEYUSE *b)
     ON condition of the given nested join, and does the same for nested joins 
     contained within this nested join.
 
-  IMPLEMENTATION
+  NOTES
     We can add accesses to the tables that are direct children of this nested 
     join (1), and are not inner tables w.r.t their neighbours (2).
     
     Example for #1 (outer brackets pair denotes nested join this function is 
     invoked for):
-
      ... LEFT JOIN (t1 LEFT JOIN (t2 ... ) ) ON cond
-     
     Example for #2:
-
      ... LEFT JOIN (t1 LEFT JOIN t2 ) ON cond
-
     In examples 1-2 for condition cond, we can add 'ref' access candidates to 
     t1 only.
-    
     Example #3:
-     
-     ... LEFT JOIN (t1, t2 JOIN t3 ON inner_cond) ON cond
-    
+     ... LEFT JOIN (t1, t2 LEFT JOIN t3 ON inner_cond) ON cond
     Here we can add 'ref' access candidates for t1 and t2, but not for t3.
-    
 */
 
 static void add_key_fields_for_nj(TABLE_LIST *nested_join_table,