…else block

…lock (#111142)

…else block (python#111142)

…else block (python#111142)

…odes before 3.13 (#17285)

Summary
--

This PR extends the documentation of the `LoadBeforeGlobalDeclaration`
check to specify the behavior on versions of Python before 3.13. Namely,
on Python 3.12, the `else` clause of a `try` statement is visited before
the `except` handlers:

```pycon
Python 3.12.9 (main, Feb 12 2025, 14:50:50) [Clang 19.1.6 ] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 10
>>> def g():
...     try:
...         1 / 0
...     except:
...         a = 1
...     else:
...         global a
...
>>> def f():
...     try:
...         pass
...     except:
...         global a
...     else:
...         print(a)
...
  File "<stdin>", line 5
SyntaxError: name 'a' is used prior to global declaration

```

The order is swapped on 3.13 (see
[CPython#111123](python/cpython#111123)):

```pycon
Python 3.13.2 (main, Feb  5 2025, 08:05:21) [GCC 14.2.1 20250128] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 10
... def g():
...     try:
...         1 / 0
...     except:
...         a = 1
...     else:
...         global a
...
  File "<python-input-0>", line 8
    global a
    ^^^^^^^^
SyntaxError: name 'a' is assigned to before global declaration
>>> def f():
...     try:
...         pass
...     except:
...         global a
...     else:
...         print(a)
...
>>>
```

The current implementation of PLE0118 is correct for 3.13 but not 3.12:
[playground](https://play.ruff.rs/d7467ea6-f546-4a76-828f-8e6b800694c9)
(it flags the first case regardless of Python version).

We decided to maintain this incorrect diagnostic for Python versions
before 3.13 because the pre-3.13 behavior is very unintuitive and
confirmed to be a bug, although the bug fix was not backported to
earlier versions. This can lead to false positives and false negatives
for pre-3.13 code, but we also expect that to be very rare, as
demonstrated by the ecosystem check (before the version-dependent check
was reverted here).

Test Plan
--

N/a

…odes before 3.13 (astral-sh#17285)

Summary
--

This PR extends the documentation of the `LoadBeforeGlobalDeclaration`
check to specify the behavior on versions of Python before 3.13. Namely,
on Python 3.12, the `else` clause of a `try` statement is visited before
the `except` handlers:

```pycon
Python 3.12.9 (main, Feb 12 2025, 14:50:50) [Clang 19.1.6 ] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 10
>>> def g():
...     try:
...         1 / 0
...     except:
...         a = 1
...     else:
...         global a
...
>>> def f():
...     try:
...         pass
...     except:
...         global a
...     else:
...         print(a)
...
  File "<stdin>", line 5
SyntaxError: name 'a' is used prior to global declaration

```

The order is swapped on 3.13 (see
[CPython#111123](python/cpython#111123)):

```pycon
Python 3.13.2 (main, Feb  5 2025, 08:05:21) [GCC 14.2.1 20250128] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> a = 10
... def g():
...     try:
...         1 / 0
...     except:
...         a = 1
...     else:
...         global a
...
  File "<python-input-0>", line 8
    global a
    ^^^^^^^^
SyntaxError: name 'a' is assigned to before global declaration
>>> def f():
...     try:
...         pass
...     except:
...         global a
...     else:
...         print(a)
...
>>>
```

The current implementation of PLE0118 is correct for 3.13 but not 3.12:
[playground](https://play.ruff.rs/d7467ea6-f546-4a76-828f-8e6b800694c9)
(it flags the first case regardless of Python version).

We decided to maintain this incorrect diagnostic for Python versions
before 3.13 because the pre-3.13 behavior is very unintuitive and
confirmed to be a bug, although the bug fix was not backported to
earlier versions. This can lead to false positives and false negatives
for pre-3.13 code, but we also expect that to be very rare, as
demonstrated by the ecosystem check (before the version-dependent check
was reverted here).

Test Plan
--

N/a