8443: Rewrite `#[derive]` removal code to be based on AST r=jonas-schievink a=jonas-schievink
We now remove any `#[derive]` before and including the one we want to expand, in the `macro_arg` query.
The same infra will be needed by attribute macros (except we only remove the attribute we're expanding, not any preceding ones).
Part of https://github.com/rust-analyzer/rust-analyzer/issues/8434 (doesn't implement the cfg-expansion yet, because that's more difficult)
8446: Undo path resolution hack for extern prelude r=jonas-schievink a=jonas-schievink
Reverts the change made in https://github.com/rust-analyzer/rust-analyzer/pull/7959
We don't populate the extern prelude for block DefMaps anymore,
so this is unnecessary
bors r+
Co-authored-by: Jonas Schievink <jonasschievink@gmail.com>