specs: fix typo in Eclipse derivation spec

Co-authored-by: Evan Richard <5766842+EvanJRichard@users.noreply.github.com>

specs/derivation.md

@@ -507,7 +507,7 @@ Each blob in a [EIP-4844] transaction really consists of `FIELD_ELEMENTS_PER_BLO
 
 Each field element is a number in a prime field of
 `BLS_MODULUS = 52435875175126190479447740508185965837690552500527637822603658699938581184513`.
-This number does not represent a full `uin256`: `math.log2(BLS_MODULUS) = 254.8570894...`
+This number does not represent a full `uint256`: `math.log2(BLS_MODULUS) = 254.8570894...`
 
 The [L1 consensus-specs](https://github.com/ethereum/consensus-specs/blob/dev/specs/deneb/polynomial-commitments.md)
 describe the encoding of this polynomial.