`provekit/common/src/whir_r1cs`: Implement Debug for WhirConfig and derive.

[recmo]

On 2025-08-29 in 2a57572 “Merge pull request #153 from worldfnd/px/refactor”:

Implement Debug for WhirConfig and derive.

pub struct WhirR1CSProof {
    #[serde(with = "serde_hex")]
    pub transcript: Vec<u8>,
}

// TODO: Implement Debug for WhirConfig and derive.
impl Debug for WhirR1CSScheme {
    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
        f.debug_struct("WhirR1CSScheme")
            .field("m", &self.m)
            .field("m_0", &self.m_0)

From provekit/common/src/whir_r1cs.rs:48