Fix typo in csharp's xat.cs

Author: makazeu

snippets/csharp/System.Security/SecureString/AppendChar/xat.cs

@@ -6,7 +6,7 @@ class Example
 {
     public static void Main()
     {
-       string msg = "The curent length of the SecureString object: {0}\n";
+       string msg = "The current length of the SecureString object: {0}\n";
        Console.WriteLine("1) Instantiate the SecureString object.");
        SecureString ss = new SecureString();
        Console.WriteLine(msg, ss.Length);
@@ -44,26 +44,26 @@ public static void Main()
 }
 // The example displays the following output:
 //       1) Instantiate the SecureString object.
-//       The curent length of the SecureString object: 0
+//       The current length of the SecureString object: 0
 //
 //       2) Append 'a' to the value.
-//       The curent length of the SecureString object: 1
+//       The current length of the SecureString object: 1
 //
 //       3) Append 'X' to the value.
-//       The curent length of the SecureString object: 2
+//       The current length of the SecureString object: 2
 //
 //       4) Append 'c' to the value.
-//       The curent length of the SecureString object: 3
+//       The current length of the SecureString object: 3
 //
 //       5) Insert 'd' at the end of the value.
-//       The curent length of the SecureString object: 4
+//       The current length of the SecureString object: 4
 //
 //       6) Remove the last character ('d') from the value.
-//       The curent length of the SecureString object: 3
+//       The current length of the SecureString object: 3
 //
 //       7) Set the second character of the value to 'b'.
-//       The curent length of the SecureString object: 3
+//       The current length of the SecureString object: 3
 //
 //       8) Delete the value of the SecureString object:
-//       The curent length of the SecureString object: 0
-//</snippet1>
+//       The current length of the SecureString object: 0
+//</snippet1>