[3.11] gh-101100: Fix sphinx warnings in c-api/gcsupport.rst (GH-114786) (#115430)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>

Author: hugovk

Doc/c-api/gcsupport.rst

@@ -64,10 +64,15 @@ rules:
    :c:macro:`Py_TPFLAGS_HAVE_GC` flag set.
 
 
-.. c:function:: TYPE* PyObject_GC_Resize(TYPE, PyVarObject *op, Py_ssize_t newsize)
+.. c:macro:: PyObject_GC_Resize(TYPE, op, newsize)
 
-   Resize an object allocated by :c:macro:`PyObject_NewVar`.  Returns the
-   resized object or ``NULL`` on failure.  *op* must not be tracked by the collector yet.
+   Resize an object allocated by :c:macro:`PyObject_NewVar`.
+   Returns the resized object of type ``TYPE*`` (refers to any C type)
+   or ``NULL`` on failure.
+
+   *op* must be of type :c:expr:`PyVarObject *`
+   and must not be tracked by the collector yet.
+   *newsize* must be of type :c:type:`Py_ssize_t`.
 
 
 .. c:function:: void PyObject_GC_Track(PyObject *op)

Doc/tools/.nitignore

@@ -4,7 +4,6 @@
 
 Doc/c-api/descriptor.rst
 Doc/c-api/float.rst
-Doc/c-api/gcsupport.rst
 Doc/c-api/init.rst
 Doc/c-api/init_config.rst
 Doc/c-api/intro.rst