Update sample.cs

- Fix first if-statement in Create method: currently checks to see if `nameValue == null` **and** `nameValue.Length == 0`. Should check if one or the other.
- Change exception thrown from above if-statement from `ArgumentNullException` to `ArgumentException` and replaced argument with `nameof` expression.
- Remove unnecessary empty lines.

Author: zacharylayne

snippets/csharp/Microsoft.Win32.SafeHandles/SafeWaitHandle/Overview/sample.cs

@@ -5,14 +5,12 @@
 
 class SafeHandlesExample
 {
-
     static void Main()
     {
         UnmanagedMutex uMutex = new UnmanagedMutex("YourCompanyName_SafeHandlesExample_MUTEX");
 
         try
         {
-
             uMutex.Create();
             Console.WriteLine("Mutex created. Press Enter to release it.");
             Console.ReadLine();
@@ -58,10 +56,8 @@ public UnmanagedMutex(string Name)
 
     public void Create()
     {
-        if (nameValue == null && nameValue.Length == 0)
-        {
-            throw new ArgumentNullException("nameValue");
-        }
+        if (nameValue == null || nameValue.Length == 0)
+            throw new ArgumentException(nameof(nameValue));
 
         handleValue = CreateMutex(mutexAttrValue,
                                         true, nameValue);
@@ -105,4 +101,4 @@ public void Release()
         ReleaseMutex(handleValue);
     }
 }
-//</Snippet1>
+//</Snippet1>