Fix remaining CPython formatter errors except for function argument separator comments (#5210)

## Summary

This fixes two problems discovered when trying to format the cpython
repo with `cargo run --bin ruff_dev -- check-formatter-stability
projects/cpython`:

The first is to ignore try/except trailing comments for now since they
lead to unstable formatting on the dummy.

The second is to avoid dropping trailing if comments through placement:
This changes the placement to keep a comment trailing an if-elif or
if-elif-else to keep the comment a trailing comment on the entire if.
Previously the last comment would have been lost.
```python
if "first if":
    pass
elif "first elif":
    pass
```

The last remaining problem in cpython so far is function signature
argument separator comment placement which is its own PR on top of this.

## Test Plan

I added test fixtures of minimized examples with links back to the
original cpython location

crates/ruff_python_formatter/resources/test/fixtures/ruff/statement/if.py

@@ -35,3 +35,30 @@ elif aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +
 
 else:
     ...
+
+# Regression test: Don't drop the trailing comment by associating it with the elif
+# instead of the else.
+# Originally found in https://github.com/python/cpython/blob/ab3823a97bdeefb0266b3c8d493f7f6223ce3686/Lib/dataclasses.py#L539
+
+if "if 1":
+    pass
+elif "elif 1":
+    pass
+# Don't drop this comment 1
+x = 1
+
+if "if 2":
+    pass
+elif "elif 2":
+    pass
+else:
+    pass
+# Don't drop this comment 2
+x = 2
+
+if "if 3":
+    pass
+else:
+    pass
+# Don't drop this comment 3
+x = 3