Fix #1449: Fix error message typo.

ICSharpCode.Decompiler/IL/Transforms/BlockTransform.cs

@@ -76,7 +76,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 		public void Run(ILFunction function, ILTransformContext context)
 		{
 			if (running)
-				throw new InvalidOperationException("Reentrancy detected. Transforms (and the CSharpDecompiler) are neither neither thread-safe nor re-entrant.");
+				throw new InvalidOperationException("Reentrancy detected. Transforms (and the CSharpDecompiler) are neither thread-safe nor re-entrant.");
 			try {
 				running = true;
 				var blockContext = new BlockTransformContext(context);

ICSharpCode.Decompiler/IL/Transforms/LoopingTransform.cs

@@ -37,7 +37,7 @@ namespace ICSharpCode.Decompiler.IL.Transforms
 		public void Run(Block block, BlockTransformContext context)
 		{
 			if (running)
-				throw new InvalidOperationException("LoopingBlockTransform already running. Transforms (and the CSharpDecompiler) are neither neither thread-safe nor re-entrant.");
+				throw new InvalidOperationException("LoopingBlockTransform already running. Transforms (and the CSharpDecompiler) are neither thread-safe nor re-entrant.");
 			running = true;
 			try {
 				int count = 1;