[DOCS] Improve discoverability for gas limit

[zainbacchus]

Brief Description of the Docs Request

Two different OP Stack chain potential customers have asked about gas limit of OP Stack. It often takes me ~4min to find the correct page when using search. https://docs.optimism.io/chain/differences

Description of the Documentation You'd Like

Can we add a callout at the top of this page? https://docs.optimism.io/builders/dapp-developers/transactions/fees or improve discoverability when user searches "gas limit"

Links to Related Pages

Provide links to any related content pages for this documentation request. This will help us to determine where the page(s) from your docs request should live
(e.g. a new node operators resource will likely link to other pages in the node operators section of the docs).

Additional Context

Provide any additional context about this documentation request. What problems did you run into that caused you to make this request?
Which existing documentation pages did you already try as a solution to your problem? Why do you think the requested page(s) will be beneficial to developers in the Optimism Collective?