[pylint] Avoid flattening nested min/max when outer call has single argument (PLW3301) (#16885)

## Summary

Fixes false positives (and incorrect autofixes) in `nested-min-max`
(`PLW3301`) when the outer `min`/`max` call only has a single argument.
Previously the rule would flatten:

```python
min(min([2, 3], [4, 1]))
```

into `min([2, 3], [4, 1])`, changing the semantics. The rule now skips
any nested call when the outer call has only one positional argument.
The pylint fixture and snapshot were updated accordingly.

## Test Plan

Ran Ruff against the updated `nested_min_max.py` fixture:

```shell
cargo run -p ruff -- check crates/ruff_linter/resources/test/fixtures/pylint/nested_min_max.py --no-cache --select=PLW3301 --preview
```

to verify that `min(min([2, 3], [4, 1]))` and `max(max([2, 4], [3, 1]))`
are no longer flagged. Updated the fixture and snapshot; all other
existing warnings remain unchanged. The code compiles and the unit tests
pass.

---

This PR was generated by an AI system in collaboration with maintainers:
@carljm, @ntBre

Fixes #16163

---------

Signed-off-by: Gene Parmesan Thomas <201852096+gopoto@users.noreply.github.com>
Co-authored-by: Brent Westbrook <brentrwestbrook@gmail.com>

Author: codex-maintainers

crates/ruff_linter/resources/test/fixtures/pylint/nested_min_max.py

@@ -55,3 +55,8 @@
     *(len(word) for word in "blah blah blah".split(" ")),
     len("Done!"),
 )
+
+
+# Outer call has a single argument, inner call has multiple arguments; should not trigger.
+min(min([2, 3], [4, 1]))
+max(max([2, 4], [3, 1]))

crates/ruff_linter/src/rules/pylint/rules/nested_min_max.rs

@@ -155,9 +155,11 @@ pub(crate) fn nested_min_max(
     let Some(min_max) = MinMax::try_from_call(func, keywords, checker.semantic()) else {
         return;
     };
-
-    if matches!(&args, [Expr::Call(ast::ExprCall { arguments: Arguments {args, .. }, .. })] if args.len() == 1)
-    {
+    // It's only safe to flatten nested calls if the outer call has more than one argument.
+    // When the outer call has a single argument, flattening would change the semantics by
+    // changing the shape of the call from treating the inner result as an iterable (or a scalar)
+    // to passing multiple arguments directly, which can lead to behavioral changes.
+    if args.len() < 2 {
         return;
     }