[mlir] Update Ch-2.md (#121379)

line 265 in the file llvm-project/mlir/docs/Tutorials/Toy/Ch-2.md 

changed mlir::OpTraits to mlir::OpTrait

Author: Vishakh2012

mlir/docs/Tutorials/Toy/Ch-2.md

@@ -262,7 +262,7 @@ class ConstantOp : public mlir::Op<
                      mlir::OpTrait::OneResult,
                      /// We also provide a utility `getType` accessor that
                      /// returns the TensorType of the single result.
-                     mlir::OpTraits::OneTypedResult<TensorType>::Impl> {
+                     mlir::OpTrait::OneTypedResult<TensorType>::Impl> {
 
  public:
   /// Inherit the constructors from the base Op class.