Clarify which "identifiers" in the C API are macros

Documentation

The "Python/C API Reference Manual" is an excellent resource but could be even better
if C macros were marked as such.

For a programmer that writes directly in C it doesn't matter which identifiers are real C functions
and which are C macros. However, when Python is used through libpython only the
C functions are available. This is the case for languages embedding Python through ffilib.

As an example: Consider the C macro PyImport_ImportModuleEx and the C function PyImport_ImportModuleLevel. They are documented in a way that makes it impossible
to guess that one is a C macro.

PyObject *PyImport_ImportModuleEx(const char *name, PyObject *globals, PyObject *locals, PyObject *fromlist)

PyObject *PyImport_ImportModuleLevel(const char *name, PyObject *globals, PyObject *locals, PyObject *fromlist, int level)

A look in "Python.c" (or friends import.h here) will reveal that PyImport_ImportModuleEx is a C macro.
But it would be a quality of life-improvement, if a simple "C Macro" were added below the
signature of C macros.

This "C macro" annotation could have the same style as the "Return value is a new reference" annotation.
(maybe with a different color).

Bắt đầu với Python/C API Reference Manual và so sánh các mục được ghi chép của PyImport_ImportModuleEx và PyImport_ImportModuleLevel. Kiểm tra import.h để xác nhận sự khác biệt giữa các macro, sau đó xác định cách tạo ra các chú thích giá trị trả về hiện có. Hoàn thành khi các macro C được đánh dấu rõ ràng trong tài liệu API mà không gắn nhãn sai cho các hàm C.