Support single delete help message in ldb (#11493)

Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/11493

Reviewed By: jowlyzhang

Differential Revision: D46325687

Pulled By: ajkr

fbshipit-source-id: ebf08477f5209104aee605496d751c857f4bb0a2

tools/ldb_tool.cc

@@ -93,6 +93,7 @@ void LDBCommandRunner::PrintHelp(const LDBOptions& ldb_options,
   BatchPutCommand::Help(ret);
   ScanCommand::Help(ret);
   DeleteCommand::Help(ret);
+  SingleDeleteCommand::Help(ret);
   DeleteRangeCommand::Help(ret);
   DBQuerierCommand::Help(ret);
   ApproxSizeCommand::Help(ret);