Docs: -X disable_remote_debug is spelled with an underscore, but the interpreter only accepts disable-remote-debug #159010

Documentation

The -X option that disables remote debugging (PEP 768) is documented as
-X disable_remote_debug (underscore) in three places:

• Doc/using/cmdline.rst (the -X list and the PYTHON_DISABLE_REMOTE_DEBUG entry)
• Doc/howto/remote_debugging.rst (two places)

But the interpreter only recognises the hyphenated spelling:
Python/initconfig.c calls config_get_xoption(config, L"disable-remote-debug"),
and python --help-xoptions prints -X disable-remote-debug. Doc/whatsnew/3.14.rst
also uses the hyphen.

Unknown -X options are silently ignored, so anyone who copies the documented
spelling ends up with remote debugging still enabled, with no error.

$ python3.14 -X disable_remote_debug -c "import sys; print(sys.is_remote_debug_enabled())"
True
$ python3.14 -X disable-remote-debug -c "import sys; print(sys.is_remote_debug_enabled())"
False

Same result on 3.15.0rc3. Because this option is a security control, the silent
no-op is the important part. Suggested fix: use disable-remote-debug in
cmdline.rst and remote_debugging.rst.

Linked PRs

• gh-159010: Fix spelling of -X disable-remote-debug in docs #159014