change parameters and add pyproperty

Author: hy-kiera

vm/src/stdlib/io.rs

@@ -701,12 +701,13 @@ mod _io {
     // TextIO Base has no public constructor
     #[pyattr]
     #[pyclass(name = "_TextIOBase", base = "_IOBase")]
+    #[derive(Debug, PyPayload)]
     struct _TextIOBase;
 
     #[pyimpl(flags(BASETYPE))]
     impl _TextIOBase {
-        #[pyattr]
-        fn encoding(vm: &VirtualMachine) -> PyObjectRef {
+        #[pyproperty]
+        fn encoding(&self, vm: &VirtualMachine) -> PyObjectRef {
             vm.ctx.none()
         }
     }