Update shell statement completion script to make use of argcomplete
Update shell statement completion script to make use of argcomplete

yugangw-msft/azure-cli,BurtBiel/azure-cli,samedder/azure-cli,samedder/azure-cli,yugangw-msft/azure-cli,QingChenmsft/azure-cli,yugangw-msft/azure-cli,QingChenmsft/azure-cli,BurtBiel/azure-cli,yugangw-msft/azure-cli,QingChenmsft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,samedder/azure-cli,samedder/azure-cli,QingChenmsft/azure-cli