fix grammr in error messages in overlapped.c (GH-3095)

diff --git a/Modules/overlapped.c b/Modules/overlapped.c
index 0aa8657..4390e9a 100644
--- a/Modules/overlapped.c
+++ b/Modules/overlapped.c
@@ -837,7 +837,7 @@
 #if SIZEOF_SIZE_T > SIZEOF_LONG
     if (self->write_buffer.len > (Py_ssize_t)ULONG_MAX) {
         PyBuffer_Release(&self->write_buffer);
-        PyErr_SetString(PyExc_ValueError, "buffer to large");
+        PyErr_SetString(PyExc_ValueError, "buffer too large");
         return NULL;
     }
 #endif
@@ -893,7 +893,7 @@
 #if SIZEOF_SIZE_T > SIZEOF_LONG
     if (self->write_buffer.len > (Py_ssize_t)ULONG_MAX) {
         PyBuffer_Release(&self->write_buffer);
-        PyErr_SetString(PyExc_ValueError, "buffer to large");
+        PyErr_SetString(PyExc_ValueError, "buffer too large");
         return NULL;
     }
 #endif