[codespell]: Fix typos.

main.go

@@ -229,7 +229,7 @@ func main() {
 		os.Exit(0)
 	}
 
-	// Check whether an authentification mechanism is pinned.
+	// Check whether an authentication mechanism is pinned.
 	authMech, _ := parsePinFile(user)
 
 	// Set XMPP connection options.
@@ -296,12 +296,12 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	// If no authentification mechanism is pinned and a SCRAM mechanism is
+	// If no authentication mechanism is pinned and a SCRAM mechanism is
 	// used, write the used mechanism to the pin file.
 	if authMech == "" && strings.HasPrefix(client.Mechanism, "SCRAM") {
 		err = writePinFile(client.Mechanism, user)
 		if err != nil {
-			log.Println("could not write authentification mechanism pin file:", err)
+			log.Println("could not write authentication mechanism pin file:", err)
 		}
 	}