restore *data* parameter of binascii.b2a_base64 to positional-only (#1352)

Modules/binascii.c

@@ -515,6 +515,7 @@ binascii_a2b_base64_impl(PyObject *module, Py_buffer *data)
 binascii.b2a_base64
 
     data: Py_buffer
+    /
     *
     newline: bool(accept={int}) = True
 
@@ -523,7 +524,7 @@ Base64-code line of data.
 
 static PyObject *
 binascii_b2a_base64_impl(PyObject *module, Py_buffer *data, int newline)
-/*[clinic end generated code: output=4ad62c8e8485d3b3 input=144fd7267a34d51c]*/
+/*[clinic end generated code: output=4ad62c8e8485d3b3 input=6083dac5777fa45d]*/
 {
     unsigned char *ascii_data;
     const unsigned char *bin_data;

Modules/clinic/binascii.c.h

@@ -97,7 +97,7 @@ exit:
 }
 
 PyDoc_STRVAR(binascii_b2a_base64__doc__,
-"b2a_base64($module, /, data, *, newline=True)\n"
+"b2a_base64($module, data, /, *, newline=True)\n"
 "--\n"
 "\n"
 "Base64-code line of data.");
@@ -112,7 +112,7 @@ static PyObject *
 binascii_b2a_base64(PyObject *module, PyObject **args, Py_ssize_t nargs, PyObject *kwnames)
 {
     PyObject *return_value = NULL;
-    static const char * const _keywords[] = {"data", "newline", NULL};
+    static const char * const _keywords[] = {"", "newline", NULL};
     static _PyArg_Parser _parser = {"y*|$i:b2a_base64", _keywords, 0};
     Py_buffer data = {NULL, NULL};
     int newline = 1;
@@ -558,4 +558,4 @@ exit:
 
     return return_value;
 }
-/*[clinic end generated code: output=4a418f883ccc79fe input=a9049054013a1b77]*/
+/*[clinic end generated code: output=35821bce7e0e4714 input=a9049054013a1b77]*/