Improve completion in IPython/Python 3.13

Improve completion in IPython/Python 3.13

IPython/Python 3.13 indirectly imports rlcompleter, and the
completer is set up to reference rlcompleter.__main__.
However, this rlcompleter.__main__ is different from the
__main__ in the REPL execution.  Therefore, this completer
cannot correctly complete the REPL globals.  To address this
issue, we override rlcompleter.__main__ with __main__ only in
the case of IPython.

* lisp/progmodes/python.el (python-shell-completion-native-setup):
Modify __PYTHON_EL_native_completion_setup().  (Bug#76205)

(cherry picked from commit a75f4449fa2aceab54f28c5ef46f82225376c2a4)