This is mainly a syntactic trick/sugar, but it's been pretty annoying
to me for a while that we can't simply pattern-match/destructure
single-variant constructors directly from the args list. A classic
example is when writing property tests:
```ak
test foo(params via both(bytearray(), int())) {
let (bytes, ix) = params
...
}
```
Now can be replaced simply with:
```
test foo((bytes, ix) via both(bytearray(), int())) {
...
}
```
If feels natural, especially coming from the JavaScript, Haskell or
Rust worlds and is mostly convenient. Behind the scene, the compiler
does nothing more than re-writing the AST as the first form, with
pre-generated arg names. Then, we fully rely on the existing
type-checking capabilities and thus, works in a seamless way as if we
were just pattern matching inline.
There's no reasons for this to be a property of only ArgName::Named to begin with. And now, with the extra indirection introduced for arg_name, it may leads to subtle issues when patterns args are used in validators.
- Add support to the formatter for these doc comments
- Add a new field to `Arg` `doc: Option<String>`
- Don't attach docs immediately after typechecking a module
- instead we should do it on demand in docs, build, and lsp
- the check command doesn't need to have any docs attached
- doing it more lazily defers the computation until later making
typechecking feedback a bit faster
- Add support for function arg and validator param docs in
`attach_module_docs` methods
- Update some snapshots
- Add put_doc to Arg
closes#685