(Add option to) display descriptions for new formulae/casks output by `brew update`

[jwodder]

Verification

• This issue's title and/or description do not reference a single formula e.g. brew install wget. If they do, open an issue at https://github.com/Homebrew/homebrew-core/issues/new/choose instead.

Provide a detailed description of the proposed feature

brew update often outputs a list of new formulae and/or casks, but these lists just consist of the formula/cask names. I would like there to be a way (CLI option and/or environment variable) to make brew update also output the description for each new formula/cask, e.g.:

New Formulae
kbt — Keyboard tester in terminal
lolcrab — Make your console colorful, with OpenSimplex noise
tiledb — Universal storage engine

New Casks
linqpad — .NET LINQ database query tool and code scratchpad

What is the motivation for the feature?

Every time I run brew update, I almost always want to find out more about the new formulae and what they do, so I have to run brew info for each of the listed formulae/casks. This feature would save me that step.

How will the feature be relevant to at least 90% of Homebrew users?

I don't know about 90%, but surely some other users would appreciate more information about what new formulae & casks do.

What alternatives to the feature have been considered?

Leaving things as they are and having to run brew info for new formulae after brew update

[tyuwags]

Is that possible to extend it to other keywords as brew makes an auto-update ?
for example, on install, its not showed

$ brew install docker
==> Auto-updating Homebrew...
==> Auto-updated Homebrew!
Updated 2 taps (homebrew/core and homebrew/cask).
==> New Formulae
jq-lsp
==> New Casks
canon-mg2500-driver