docs: fix grammar in comments

[odupontt]

• Fix incorrect article usage: "an struct/handle/negative" → "a struct/handle/negative"
• Fix typo in comment: "Assert that err_data bye the statement that was removed above." → " Assert err_data is produced by the statement that was removed above."

[reviewable-StarkWare]

This change is 

[orizi]

@orizi reviewed 3 of 4 files at r1, all commit messages.
Reviewable status: 3 of 4 files reviewed, 1 unresolved discussion

---

crates/cairo-lang-lowering/src/panic/mod.rs line 142 at r1 (raw file):

            panic!("Expected a tuple construct before the panic.");
        };
        // Assert `err_data` by the statement that was removed above.

Suggestion:

        // Assert `err_data` is produced by the statement that was removed above.

[odupontt]

@orizi Hi,
Thanks for the suggestion! I’ve updated the comment

[orizi]

@orizi reviewed 1 of 1 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @odupontt)