Description: Fix spelling mistake.
--- a/mongodb_exporter.go
+++ b/mongodb_exporter.go
@@ -28,21 +28,21 @@
 var (
 	listenAddressFlag = flag.String("web.listen-address", ":9001", "Address on which to expose metrics and web interface.")
 	metricsPathFlag   = flag.String("web.metrics-path", "/metrics", "Path under which to expose metrics.")
-	webTLSCert        = flag.String("web.tls-cert", "", "Path to PEM file that conains the certificate (and optionally also the private key in PEM format).\n"+
+	webTLSCert        = flag.String("web.tls-cert", "", "Path to PEM file that contains the certificate (and optionally also the private key in PEM format).\n"+
 		"    \tThis should include the whole certificate chain.\n"+
 		"    \tIf provided: The web socket will be a HTTPS socket.\n"+
 		"    \tIf not provided: Only HTTP.")
-	webTLSPrivateKey = flag.String("web.tls-private-key", "", "Path to PEM file that conains the private key (if not contained in web.tls-cert file).")
-	webTLSClientCa   = flag.String("web.tls-client-ca", "", "Path to PEM file that conains the CAs that are trused for client connections.\n"+
+	webTLSPrivateKey = flag.String("web.tls-private-key", "", "Path to PEM file that contains the private key (if not contained in web.tls-cert file).")
+	webTLSClientCa   = flag.String("web.tls-client-ca", "", "Path to PEM file that contains the CAs that are trused for client connections.\n"+
 		"    \tIf provided: Connecting clients should present a certificate signed by one of this CAs.\n"+
 		"    \tIf not provided: Every client will be accepted.")
 
 	mongodbURIFlag = flag.String("mongodb.uri", mongodbDefaultURI(), "Mongodb URI, format: [mongodb://][user:pass@]host1[:port1][,host2[:port2],...][/database][?options]")
-	mongodbTLSCert = flag.String("mongodb.tls-cert", "", "Path to PEM file that conains the certificate (and optionally also the private key in PEM format).\n"+
+	mongodbTLSCert = flag.String("mongodb.tls-cert", "", "Path to PEM file that contains the certificate (and optionally also the private key in PEM format).\n"+
 		"    \tThis should include the whole certificate chain.\n"+
 		"    \tIf provided: The connection will be opened via TLS to the MongoDB server.")
-	mongodbTLSPrivateKey = flag.String("mongodb.tls-private-key", "", "Path to PEM file that conains the private key (if not contained in mongodb.tls-cert file).")
-	mongodbTLSCa         = flag.String("mongodb.tls-ca", "", "Path to PEM file that conains the CAs that are trused for server connections.\n"+
+	mongodbTLSPrivateKey = flag.String("mongodb.tls-private-key", "", "Path to PEM file that contains the private key (if not contained in mongodb.tls-cert file).")
+	mongodbTLSCa         = flag.String("mongodb.tls-ca", "", "Path to PEM file that contains the CAs that are trused for server connections.\n"+
 		"    \tIf provided: MongoDB servers connecting to should present a certificate signed by one of this CAs.\n"+
 		"    \tIf not provided: System default CAs are used.")
 	mongodbTLSDisableHostnameValidation = flag.Bool("mongodb.tls-disable-hostname-validation", false, "Do hostname validation for server connection.")