minor doc edits for new knob SOCKET_LISTEN_BACKLOG  #4393
Enhance version history item and remove a usage of the
no-longer-used 'condor-reuse-slot<N>' user name #4388
document the default value of GSI_DAEMON_DIRECTORY #4390
minor 8.2.0 version history item edit  #4384
super minor 8.2.0 version history item edit #4391
minor 8.2.0 version history item edit (and fix spelling) #4392