Merge #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 b077f34..2b39f66 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -1817,7 +1817,7 @@
     self->ok = 0;
     self->detached = 0;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|n:BufferedReader", kwlist,
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|n:BufferedWriter", kwlist,
                                      &raw, &buffer_size)) {
         return -1;
     }
@@ -2446,7 +2446,7 @@
     self->ok = 0;
     self->detached = 0;
 
-    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|n:BufferedReader", kwlist,
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|n:BufferedRandom", kwlist,
                                      &raw, &buffer_size)) {
         return -1;
     }