Enable pretty-printing for PEP-649 annotated functions (ipython#15095)

This PR detects the possibility of such functions by importing
annotationlib.Format from inspect, and wraps inspect.signature in a
partial that sets annotation_format=Format.FORWARDREF.

This may be more proof-of-concept than final form; I won't be offended
if you want to scrap this and tackle the issue a different way :)

I'm also not sure this is actually enough to support all possibilities,
but it at least gets us from

```python
In [1]: def test(p: Annotated): pass

In [2]: test

<huge traceback elided>

NameError: name 'Annotated' is not defined

In [3]:
```

to

```python
In [1]: def test(p: Annotated): pass

In [2]: test
Out[2]: <function __main__.test(p: Annotated)>
```

Author: Carreau

IPython/lib/pretty.py

@@ -109,6 +109,14 @@ def _repr_pretty_(self, p, cycle):
 
 from typing import Dict
 
+# Allow pretty-printing of functions with PEP-649 annotations
+if sys.version_info >= (3, 14):
+    from annotationlib import Format
+    from functools import partial
+
+    signature = partial(signature, annotation_format=Format.FORWARDREF)
+
+
 __all__ = ['pretty', 'pprint', 'PrettyPrinter', 'RepresentationPrinter',
     'for_type', 'for_type_by_name', 'RawText', 'RawStringLiteral', 'CallExpression']
 

tests/test_pretty.py

@@ -543,6 +543,31 @@ def meaning_of_life(question=None):
     assert "meaning_of_life(question=None)" in pretty.pretty(meaning_of_life)
 
 
+def test_annotated_function_pretty():
+    "Test pretty print of a function with PEP-649 annotations"
+    # Confirm that the name is not in scope
+    try:
+        b
+    except NameError:
+        pass
+    else:
+        assert False, "Unexpected 'b' found in scope"
+    try:
+        def f(a: b): pass
+    except NameError as e:
+        if e.name == 'b':
+            # PEP-649 not available
+            return
+        raise
+    # Check whether __future__.annotations is in effect
+    # It probably shouldn't be, but to be sure:
+    import __future__
+    if f.__code__.co_flags & __future__.annotations.compiler_flag:
+        assert "f(a: 'b')" in pretty.pretty(f)
+    else:
+        assert "f(a: b)" in pretty.pretty(f)
+
+
 class OrderedCounter(Counter, OrderedDict):
     "Counter that remembers the order elements are first encountered"