message: Fix old terminology in renderdoccmd documentation
diff: @@ -527,7 +527,7 @@ struct ReplayCommand : public Command
  }
  virtual const char *Description()
  {
  - return "Replay the log file and show the backbuffer on a preview window.";
  + return "Replay a capture and show the backbuffer on a preview window.";
  }
  virtual bool IsInternalOnly() { return false; }
  virtual bool IsCaptureCommand() { return false; }
  