Show header for formatter comment decoration info (#7228)
Show header for formatter comment decoration info
**Summary** Show a header in the formatter comment decoration debug
output that shows which node is preceding/following/enclosing
(https://github.com/astral-sh/ruff/pull/6813#issuecomment-1708119550). I
kept this intentionally condensed to make it easy to use this is a small
sidebar without vertical scrolling.
```console
$ cargo run --bin ruff_python_formatter -- --emit stdout --print-comments scratch.py
# Comment decoration: Range, Preceding, Following, Enclosing, Comment
17..20, Some((ParameterWithDefault, 6..10)), None, (Parameters, 5..22), "# a"
44..47, Some((StmtExpr, 28..39)), Some((StmtExpr, 52..60)), (StmtFunctionDef, 0..60), "# b"
77..80, None, None, (ExprList, 71..82), "# c"
{
Node {
kind: ParameterWithDefault,
range: 6..10,
source: `x=[]`,
}: {
...
```
**Test Plan** It's debug output.
