[tool proposal] Determine enabled lint rules and their definitions

[parlough]

To help agents create code that follows a project's style expectations on the first try, it might be interesting to provide a tool that exposes a list of all enabled lint rules (including transitively included) for a file. The tool could provide the short description of each rule as well as the link to its docs to learn more if necessary.

\cc @bwilkerson I've been thinking more and more it might make sense to include the messages.yaml files in the built SDK directories (or a compiled JSON version). Then tools like this, the analysis server, and IDEs can find and surface the complete lint and diagnostic docs without redirecting developers (or agents) to the web. That would also open other use cases like surfacing full guidelines for agents trying to resolve specific diagnostics.

[bwilkerson]

@jakemac53

[jakemac53]

I think this probably should be at a project level, allowing the agent to ask for the lint rules enabled in a specific "root".

We may want to try and also look recursively in the subdirectories in case they have different rules.

[gspencergoog]

It also might be nice if this were just an option on the dart analyze command itself, to print out the list of lints in effect.

[bwilkerson]

Given that analysis options files can be placed in any directory (for example, to allow different lints to apply to test code), we'd want a format that allowed for different rule sets in different directories. I don't know what format we'd want to produce, but it would be fairly easy to write such a tool.