11043: fix: fix incorrect mismatched argument count diagnostic with `std::arch` functions r=jonas-schievink a=jonas-schievink
Adds basic support for `#[rustc_legacy_const_generics]`.
Fixes https://github.com/rust-analyzer/rust-analyzer/issues/10009
Full support would involve actually checking call arguments against the right expected types.
bors r+
Co-authored-by: Jonas Schievink <jonas.schievink@ferrous-systems.com>
7f28b49759