NS SUSPEND now req 'ban' capabs

irc/nickserv.go

 command lists all current suspensions.`,
 			helpShort: `$bSUSPEND$b manages account suspensions`,
 			minParams: 1,
-			capabs:    []string{"accreg"},
+			capabs:    []string{"ban"},
 		},
 		"rename": {
 			handler: nsRenameHandler,