Update the docs/developer-guide/architecture page

[VictorHom]

Page link - https://eslint.org/docs/developer-guide/architecture

I believe the architecture has changed over time and it makes sense to update this page so new contributors can acclimate more quickly to what/which file does what (at least a high level overview)

Most of the page is still accurate, but one part didn't seem up-to-date (since the file doesn't exist anymore):

lib/eslint.js - this is the core eslint object that does code verifying based on configuration options. This file does no file I/O and does not interact with the console at all. For other Node.js programs that have JavaScript text to verify, they would be able to use this interface directly.

[VictorHom]

if the issue makes sense, I can look into and help with updating the documentation :)

[platinumazure]

Hi @VictorHom, thanks for the issue!

Yes, we absolutely should update this document! lib/eslint.js has basically been replaced by lib/linter.js (exports class Linter), but there has also been a lot of decomposition of some of the functionality previously in lib/eslint.js into ancillary files.

We could probably start by replacing lib/eslint.js with lib/linter.js in the docs.