Sub-tables defined using both table and dotted keys are flagged as duplicates

[tpoliaw]

Describe the bug
If a table has some entries defined using dotted.syntax and some using [tables], they are flagged as duplicates and fail to parse. This is allowed in the spec (end of the table section) as The [table] form can, however, be used to define sub-tables within tables defined via dotted keys.

To Reproduce

fn main() {
    let src = r#"
        abc.foo = "one"
        [abc.bar]
        fizz = 1
        buzz = 2
        "#;
    let table = toml_span::parse(src);
    println!("{table:?}");
}

Gives the duplicate key error

Err(
    Error {
        kind: DuplicateKey {
            key: "abc",
            first: Span {
                start: 9,
                end: 12,
            },
        },
        span: Span {
            start: 34,
            end: 37,
        },
        line_info: Some(
            (
                2,
                9,
            ),
        ),
    },
)

Expected behavior
The above example to be parsed into the equivalent of {'abc': {'bar': {'fizz': 1, 'buzz': 2}, 'foo': 'one'}}

Device:

• OS: Linux
• Version 0.3.0
• rustc 1.82.0