docs(tools): add documentation for deno compile cmd

[fabiante]

This PR adds documentation for the new deno compile command introduced in PR #8539 and discussed in #986

[CLAassistant]

All committers have signed the CLA.

[fabiante]

@lucacasonato I figure you may be the correct person to review this. Please excuse me if not or I am unintentionally spamming.

[bartlomieju]

Thanks @fabiante, make sure to run tools/format.js and tools/lint.js to make CI pass

[fabiante]

Hi Bartek, I'd love to. Turns out in my local project third_party is empty, dprint therefore can't be called and I don't know how to fix that. I tried building Deno myself, hoping that would populate the given folder but it doesn't. I guess I am missing something very obvious here? Sorry to bother.

[bartlomieju]

@fabiante you need to check out git submodules, following command should do the trick: git submodule update --init --recursive

[ry]

Thanks - please update docs/toc.json too

[bartlomieju]

LGTM, thank you @fabiante!