Delete unused associated constant from lexical

    warning: associated constant `NEGATIVE_INFINITY_BITS` is never used
       --> src/lexical/num.rs:223:11
        |
    175 | pub trait Float: Number {
        |           ----- associated constant in this trait
    ...
    223 |     const NEGATIVE_INFINITY_BITS: Self::Unsigned;
        |           ^^^^^^^^^^^^^^^^^^^^^^
        |
        = note: `#[warn(dead_code)]` on by default

src/lexical/num.rs

@@ -219,8 +219,6 @@ pub trait Float: Number {
 
     /// Positive infinity as bits.
     const INFINITY_BITS: Self::Unsigned;
-    /// Positive infinity as bits.
-    const NEGATIVE_INFINITY_BITS: Self::Unsigned;
     /// Size of the significand (mantissa) without hidden bit.
     const MANTISSA_SIZE: i32;
     /// Bias of the exponent
@@ -320,7 +318,6 @@ impl Float for f32 {
     const HIDDEN_BIT_MASK: u32 = 0x00800000;
     const MANTISSA_MASK: u32 = 0x007FFFFF;
     const INFINITY_BITS: u32 = 0x7F800000;
-    const NEGATIVE_INFINITY_BITS: u32 = Self::INFINITY_BITS | Self::SIGN_MASK;
     const MANTISSA_SIZE: i32 = 23;
     const EXPONENT_BIAS: i32 = 127 + Self::MANTISSA_SIZE;
     const DENORMAL_EXPONENT: i32 = 1 - Self::EXPONENT_BIAS;
@@ -379,7 +376,6 @@ impl Float for f64 {
     const HIDDEN_BIT_MASK: u64 = 0x0010000000000000;
     const MANTISSA_MASK: u64 = 0x000FFFFFFFFFFFFF;
     const INFINITY_BITS: u64 = 0x7FF0000000000000;
-    const NEGATIVE_INFINITY_BITS: u64 = Self::INFINITY_BITS | Self::SIGN_MASK;
     const MANTISSA_SIZE: i32 = 52;
     const EXPONENT_BIAS: i32 = 1023 + Self::MANTISSA_SIZE;
     const DENORMAL_EXPONENT: i32 = 1 - Self::EXPONENT_BIAS;