Added description of history --clear flag to change log

Author: kmvanbrunt

CHANGELOG.md

@@ -2,6 +2,8 @@
 * Bug Fixes
     * Fixed bug when StatementParser ``__init__()`` was called with ``terminators`` equal to ``None``
     * Fixed bug when ``Cmd.onecmd()`` was called with a raw ``str``
+* Enhancements
+    * Added ``--clear`` flag to ``history`` command that clears both the command and readline history.
 * Deletions
     * The ``CmdResult`` helper class which was *deprecated* in the previous release has now been deleted
         * It has been replaced by the improved ``CommandResult`` class