docs(sidecar): document base fee increase function

bolt-sidecar/src/common.rs

@@ -22,6 +22,9 @@ pub const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
 /// Calculates the max_basefee `slot_diff` blocks in the future given a current basefee (in wei).
 /// Returns None if an overflow would occur.
 /// Cfr. https://github.com/flashbots/ethers-provider-flashbots-bundle/blob/7ddaf2c9d7662bef400151e0bfc89f5b13e72b4c/src/index.ts#L308
+///
+/// NOTE: this increase is correct also for the EIP-4844 blob base fee:
+/// See https://eips.ethereum.org/EIPS/eip-4844#base-fee-per-blob-gas-update-rule
 pub fn calculate_max_basefee(current: u128, block_diff: u64) -> Option<u128> {
     // Define the multiplier and divisor for fixed-point arithmetic
     let multiplier: u128 = 1125; // Represents 112.5%