- `l1FeeScalar` is actually `scalar` in the code.
- `l1FeeOverhead` is actually `overhead` in the code.

Didn't change `exec-engine.md` because there those variable names are defined correctly.

Also added update config transaction type 3 to the doc.

Based on https://github.com/sherlock-audit/2023-01-optimism-judging/blob/b7921698c1c537714c5f2021aa46ce0a1935ba39/1-specs-findings/1-processed/1-true/names/213.md

Closing: DEVRL-847