refactor: fix clippy lints

[sandr01d]

Goal

Fixes clippy lints without introducing any actual changes. The lint regarding usage of parse instead of from_str_radix shows up in projects using ts-rs as a dependency due to it being used in the derive macro for TS. This trips over the CI in the project I'm using ts-rs with.

Changes

Implements the changes suggested by clippy without introducing any changes in behavior. I added an #[allow(clippy::enum_variant_names)] for the Optional enum because changing the names of the variants would not make any sense IMO.
There are two lints left regarding std::path::absolute only being available in Rust 1.79.0 and the project using 1.78.0. Guess the best way to resolve that is to update the Rust version, so I left out those ones.

Checklist

• I have followed the steps listed in the Contributing guide.
• If necessary, I have added documentation related to the changes made.
• I have added or updated the tests related to the changes made.

[gustavo-shigueo]

Hi @sandr01d, thanks for the PR! There is only one test I'd like you to revert as the intention is to make sure export_to works with any expression, not just string literals

[gustavo-shigueo]

There are two lints left regarding std::path::absolute only being available in Rust 1.79.0 and the project using 1.78.0.

This had me really concerned that the MSRV check was giving invalid passes until I checked that both uses are in the tests lol

[sandr01d]

Thanks for the quick review, everything should be addressed @gustavo-shigueo

[gustavo-shigueo]

LGTM