feat(hax-lib&backend): F*: support for SMT patterns

[W95Psp]

This PR adds support for SMT patterns in lemmas written in Rust.

For example:

fn dummy_function(x: u32) -> u32 {
    x
}

#[hax::lemma]
#[hax::fstar::smt_pat(x)]
fn apply_dummy_function_lemma(x: u32) -> Proof<{ x == dummy_function(x) }> {}