tools: remove readability/fn_size rule
Due to https://github.com/nodejs/node/pull/53927 I had to update the v22.x-staging branch to include a // NOLINT(readability/fn_size)
https://github.com/nodejs/node/blob/v22.x-staging/src/node_options.cc#L890
I'm questioning whether having this rule is really necessary or beneficial. This lint didn't fail on main
(yet) because we have more code on this specific function in v22.x-staging. So, this will likely appear in a PR soon, and I think that dropping this rule instead of adding a NOLINT
comment is a much better option.