bpo-40204, doc: Fix syntax of C variables (GH-21846)
For example, fix the following Sphinx 3 errors:
Doc/c-api/buffer.rst:102: WARNING: Error in declarator or parameters
Invalid C declaration: Expected identifier in nested name. [error at 5]
void \*obj
-----^
Doc/c-api/arg.rst:130: WARNING: Unparseable C cross-reference: 'PyObject*'
Invalid C declaration: Expected end of definition. [error at 8]
PyObject*
--------^
The modified documentation is compatible with Sphinx 2 and Sphinx 3.
diff --git a/Doc/c-api/tuple.rst b/Doc/c-api/tuple.rst
index c14cb2d..bf751e44 100644
--- a/Doc/c-api/tuple.rst
+++ b/Doc/c-api/tuple.rst
@@ -161,7 +161,7 @@
.. c:type:: PyStructSequence_Field
Describes a field of a struct sequence. As a struct sequence is modeled as a
- tuple, all fields are typed as :c:type:`PyObject\*`. The index in the
+ tuple, all fields are typed as :c:type:`PyObject*`. The index in the
:attr:`fields` array of the :c:type:`PyStructSequence_Desc` determines which
field of the struct sequence is described.