cmd/puppeth: fix typos and review suggestions

cmd/puppeth/module_dashboard.go

cmd/puppeth/module_ethstats.go

cmd/puppeth/module_explorer.go

cmd/puppeth/module_faucet.go

cmd/puppeth/module_nginx.go

cmd/puppeth/module_node.go

cmd/puppeth/module_wallet.go

cmd/puppeth/wizard_dashboard.go

cmd/puppeth/wizard_ethstats.go

cmd/puppeth/wizard_explorer.go

cmd/puppeth/wizard_faucet.go

cmd/puppeth/wizard_node.go

cmd/puppeth/wizard_wallet.go