Remove invalid simplesect tags to eliminate validation warning
Remove invalid simplesect tags to eliminate validation warning

* /trunk/doc/book/book/ch06.xml: Fix validation warning.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion