bug#25753: 25.2; Python mode shell interaction not working 100%

[Carlos Pita]

I’m having this issue with emacs 28 in macOS Big Sur, my python interpreter was 
installed using brew and has readline support:

```
Python 3.9.7 (default, Sep  3 2021, 12:37:55)
[Clang 12.0.5 (clang-1205.0.22.9)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import readline; print (readline.__doc__)
Importing this module enables command line editing using GNU readline.
```

But:

```
Warning (python): Your ‘python-shell-interpreter’ doesn’t seem to support 
readline, yet ‘python-shell-completion-native-enable’ was t and "python3" is 
not part of the ‘python-shell-completion-native-disabled-interpreters’ list.  
Native completions have been disabled locally.  Disable showing Disable logging
```

Is this expected? The thread above seems to suggest that it should work, but 
maybe I’m misreading it.

Thanks