message: Fix renderdoccmd help screen
  The help information for the 'convert' command in the
  renderdoccmd was incorrect.
diff: @@ -638,7 +638,7 @@ struct ConvertCommand : public Command
  formatOptions.add(f.name);
  parser.add<string>("filename", 'f', "The file to convert from.", false);
  - parser.add<string>("output", 'o', "The file to convert from.", false);
  + parser.add<string>("output", 'o', "The file to convert to.", false);
  parser.add<string>("input-format", 'i', "The format of the input file.", false, "",
  formatOptions);
  parser.add<string>("convert-format", 'c', "The format of the output file.", false, "",
  @@ -646,7 +646,7 @@ struct ConvertCommand : public Command
  parser.add("list-formats", '\0', "print a list of target formats");
  parser.stop_at_rest(true);
  }
  - virtual const char *Description() { return "Run internal tests such as unit tests."; }
  + virtual const char *Description() { return "Convert between capture formats."; }
  virtual bool IsInternalOnly() { return false; }
  virtual bool IsCaptureCommand() { return false; }
  virtual int Execute(cmdline::parser &parser, const CaptureOptions &)
  