added documention for pegasus.log.memory.usage
added documention for pegasus.log.memory.usage

pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus,pegasus-isi/pegasus