text-objects: add test capture & elixir queries

[connorlay]

See #2792

[the-mikedavis]

This is looking good :)

I might push a commit or two with queries for more languages if that's alright

[connorlay]

I might push a commit or two with queries for more languages if that's alright

Go for it! Which languages did you have in mind?

[the-mikedavis]

I was thinking at least Rust but also Erlang for my sake 😄

For Rust, we can capture the function following the #[test] attribute.

For a few of languages (Erlang EUnit tests and Gleam Gleeunit for example) we could have the captures be pretty much the same as @function.* but only for those functions with a name that have a name that ends in _test.

[connorlay]

@the-mikedavis What do you think about queries for languages that have a number of popular test frameworks, like JavaScript?

This leads me to wonder if Helix should support some kind of opt-in queries for specific frameworks? Highlights and textobjects for the Phoenix router DSL would be handy to have available, but I don't think belongs in the core Elixir queries.

[the-mikedavis]

Hmm I think we should aim to only support official language tooling in the core and leave framework-specific features to plugins (once implemented). Especially if two frameworks conflict, it's hard to be rigorous about which one should get support.

For this feature in particular though I don't see any harm in supporting javascript testing frameworks for example

[the-mikedavis]

Thanks for working on this @connorlay, this is great!