fix warnings and lints

[thor314]

Fixes a few lints and warnings.

• cargo clippy --fix
• ? operator
• lint by hand

---

This change is 

[orizi]

Reviewed 9 of 9 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @thor314)

---

crates/cairo-lang-sierra-ap-change/src/compute.rs line 40 at r1 (raw file):

enum ApTrackingBase {
    FunctionStart(FunctionId),
    #[allow(dead_code)]

why is it deadcode for you?

Code quote:

    #[allow(dead_code)]

[thor314]

@orizi
clippy flags the enum variant as unused. This indicates that the enum variant is not directly consumed. A grep for the variant shows that it's used in one place, so this warning may be a linting bug, rather than a bug in the library. I can comment it as such if helpful.

[orizi]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @thor314)

a discussion (no related file):
@gilbens-starkware for 2nd eye

---

[gilbens-starkware]

Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @thor314)

[orizi]

Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @thor314)