#17275: Fix class name in init errors in C bufferedio classes.

This fixes an apparent copy-and-paste error.

Patch by Manuel Jacob.
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index bb77acc..a8278d4 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1702,7 +1702,7 @@
     self->ok = 0;
     self->detached = 0;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|nn:BufferedReader", kwlist,
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|nn:BufferedWriter", kwlist,
                                      &raw, &buffer_size, &max_buffer_size)) {
         return -1;
     }
@@ -2339,7 +2339,7 @@
     self->ok = 0;
     self->detached = 0;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|nn:BufferedReader", kwlist,
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|nn:BufferedRandom", kwlist,
                                      &raw, &buffer_size, &max_buffer_size)) {
         return -1;
     }