Unhandled case of a walrus operator in the output part of a list comprehension

[FasterSpeeding]

Describe the bug
Griffe raises a KeyError when it encounters a walrus operator (NamedExpr) in the output part of a list, set or dict comprehension, or a generator expression.

To Reproduce
Steps to reproduce the behavior:

1. Save the following example code to "test.py"

def bar(value):
    return value

foo = [result if (result := bar(v)) else v for v in (1,2,3)]

2. Run command griffe dump -s . test
3. Scroll up to the start of the command's output
4. See an error like the following:

ERROR      Failed to unparse node <ast.ListComp object at 0x000001C826AAF4C0> at test.py:4: <class 'ast.NamedExpr'>
Traceback (most recent call last):
  File "C:\Users\Lucina\PycharmProjects\tanjun\venv\lib\site-packages\griffe\agents\nodes.py", line 1240, in safe_get_value
    return get_value(node)
  File "C:\Users\Lucina\PycharmProjects\tanjun\venv\lib\site-packages\griffe\agents\nodes.py", line 1226, in get_value
    return _node_value_map[type(node)](node)
  File "C:\Users\Lucina\PycharmProjects\tanjun\venv\lib\site-packages\griffe\agents\nodes.py", line 1005, in _get_listcomp_value
    element = _get_value(node.elt)
  File "C:\Users\Lucina\PycharmProjects\tanjun\venv\lib\site-packages\griffe\agents\nodes.py", line 1212, in _get_value
    return _node_value_map[type(node)](node)
  File "C:\Users\Lucina\PycharmProjects\tanjun\venv\lib\site-packages\griffe\agents\nodes.py", line 965, in _get_ifexp_value
    return f"{_get_value(node.body)} if {_get_value(node.test)} else {_get_value(node.orelse)}"
  File "C:\Users\Lucina\PycharmProjects\tanjun\venv\lib\site-packages\griffe\agents\nodes.py", line 1212, in _get_value
    return _node_value_map[type(node)](node)
KeyError: <class 'ast.NamedExpr'>

Expected behavior
This should parse without error as this is valid syntax (which runs fine).

System (please complete the following information):

• griffe version: griffe-0.27.1
• Python version: 3.10.9
• OS: Windows

[pawamoy]

Hey @FasterSpeeding, thanks for the report! Fixed in v0.27.2.