Update third-party.rst
Update third-party.rst

Fix some ReST formatting.
dropwizard/metrics,cirrus-dev/metrics,jasw/metrics,ind9/metrics,rexren/metrics,unitsofmeasurement/metrics,ohr/metrics,kevintvh/metrics,mattnelson/metrics,signalfx/metrics,AltitudeDigital/metrics,valery1707/dropwizard-metrics,mnuessler/metrics,dropwizard/metrics,slovdahl/metrics,jplock/metrics,mt0803/metrics,dropwizard/metrics,randomstatistic/metrics,ChetnaChaudhari/metrics,infusionsoft/yammer-metrics,tempredirect/metrics,gburton1/metrics,mveitas/metrics,mspiegel/metrics,timezra/metrics,mveitas/metrics,bentatham/metrics,Banno/metrics,wfxiang08/metrics,mtakaki/metrics,thelastpickle/metrics,egymgmbh/metrics,infusionsoft/yammer-metrics,slachiewicz/metrics,chenxianghua2014/metrics,gburton1/metrics