docs generator: attrs.source() becomes `str` which is unhelpful

[lf-]

Synopsis: There are many different types of str that can be used in rules that have significant semantic meaning: sources, target selectors, and more. However, they're squashed into str at docs generation time, which is frustrating as a user, especially if the attrs in question are undocumented (something which needs improvement in the prelude overall).

Definition:

buck2/prelude/decls/core_rules.bzl

Line 206 in 425b675

"resources": attrs.list(attrs.source(), default = []),

Result:

def command_alias(
    *,
    # ...
    platform_exe: dict[str, str] = {},
    resources: list[str] = [],
    # ...
) -> None

Web version: https://buck2.build/docs/prelude/rules/core/command_alias/