gh-157208: Fix the ctypes.util.struct documentation

[fedonman]

The anonymous-field example for @struct used Annotated, CFieldInfo, c_ssize_t and c_void_p with no imports, so copying it out of the page raised NameError; this adds the imports and indents the example body four spaces to match the example above it. It also gives layout its default in the signature line, which had rendered an optional parameter as required.

• Issue: ctypes.util.struct example does not run and layout looks required #157208

[read-the-docs-community]

Documentation build overview

📚 cpython-previews | 🛠️ Build #34471854 | 📁 Comparing e81da50 against main (894af95)

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2 files changed

± library/ctypes.html
± library/curses.html

[aisk]

Hi, I found that some other examples in this file are also using three spaces for indentation. Could you fix them here too? Other than that, LGTM.

cpython/Doc/library/ctypes.rst

Lines 709 to 711 in 894af95

	@wrap_dll_function(dll_to_wrap)
	def function_ptr_name(arg_name: ctypes_type, ...) -> ctypes_type:
	"""Optional docstring. There should be no function body."""

cpython/Doc/library/ctypes.rst

Lines 729 to 731 in 894af95

	@wrap_dll_function(ctypes.pythonapi)
	def PyObject_GetAttrString(op: ctypes.py_object, attr: ctypes.c_char_p) -> ctypes.py_object:
	pass