[mlir][bufferization] fixed typo in to_memref doc

[aartbik]

rebased with main

[pifon2a]

Thank you, Aart!

mlir/include/mlir/Dialect/Bufferization/IR/BufferizationOps.td

def Bufferization_ToMemrefOp : Bufferization_Op<"to_memref",
   let description = [{
     Casts a tensor to a memref.
 
     ```mlir
     // Result type is tensor<4x?xf32>
     %12 = bufferization.to_memref %10 : memref<4x?xf32, #map0, 42>
     ```
 
-    Note, that mutating the result of the to_buffer operation leads to
+    Note, that mutating the result of the to_memref operation leads to
     undefined behavior.
 
     This operation is a specialized variant of the built-in
     unrealized_conversion_cast and is intended for use in the context of
     gradual bufferization.
   }];
 
   let arguments = (ins AnyTensor:$tensor);