Fix inconsistency

[YichiZhang0613]

Their comments both requires string.len() <= SpanValue::MAX as usize while the code checks string.len() < SpanValue::MAX as usize. It looks like string.len() == SpanValue::MAX as usize should be allowed semantically and thus the code should be fixed.

///  # Panics
///  This function will panic if the input string's length is greater than [`SpanValue::MAX`].
pub fn full(string: &str) -> Self {
    assert!(
        string.len() < SpanValue::MAX as usize,
        "Length of `Span::full` input must be less than `SpanValue::MAX!`"
    );
...

/// # Panics
    /// This function will panic if the input string's length is greater than [`SpanValue::MAX`].
    pub fn full(string: &str) -> Self {
        assert!(
            string.len() < SpanValue::MAX as usize,
            "Length of `Span::full` input must be less than or equal to `SpanValue::MAX!`"
        );
...

[akiramusic000]

Thanks for the PR! Sorry I didn't respond to it sooner. Before I merge this, could you add your name to CONTRIBUTORS.md? Thanks!

Also, ignore the failing checks, those are from newer Clippy lints.

[YichiZhang0613]

Thanks for the PR! Sorry I didn't respond to it sooner. Before I merge this, could you add your name to CONTRIBUTORS.md? Thanks!

Also, ignore the failing checks, those are from newer Clippy lints.

OK!